Phylogeny and taxonomy of the shore-fly tribe Ephydrini with comments on related tribes in Ephydrinae (Diptera: Ephydridae)

ABSTRACT

Ephydrini comprises 118 species (plus seven nomina dubia species) that are distributed in all biogeographical regions except Antarctica. The tribe currently includes 13 genera, of which three (Calocoenia Mathis, Ephydra Fallén, Paracoenia Cresson) include subgenera. The subgenus Ephydra and three other genera (Neoephydra Mathis, Notiocoenia Mathis, Setacera Cresson) include species groups. Representatives of all these groupings (genera, subgenera, and in most cases also species groups) are included in the phylogenetic analysis and taxonomic treatment. To test the monophyly of Ephydrini and to understand phylogenetic relationships among genera, a cladistic analysis was performed using equal and implicit character weightings based on the morphology of adult males and females. Species of all 13 genera of Ephydrini from different geographical regions were included to account for morphological and phylogenetic diversity. Also included in the analysis are species of the other tribes of the subfamily Ephydrinae to provide greater perspective on the phylogenetic position of Ephydrini within the subfamily and to serve as outgroups. In our analyses, cladograms from both equal weighting and implied weighting resulted in cladograms of 261 steps in length. The tribes Ephydrini, Dagini, and Scatellini were recovered as monophyletic lineages. The tribe Dagini is the sister lineage to the node giving rise to the tribes Scatellini and Ephydrini, and the latter two tribes were recovered as sister groups. Within Ephydrini, the implied weighting cladogram provided higher resolution among terminal taxa with the same number of steps and is thus our preferred cladogram. In this cladogram, all currently valid genera, including subgenera and species groups, were recovered as monophyletic lineages. Thus, no taxonomic changes are needed at the genus-group level. In the taxonomic section, the tribe Ephydrini is characterized, as are all included genera within the tribe. In addition, keys to all genera, subgenera, and species groups are provided to facilitate their identification.

KEYWORDS:
Cladistic analysis; Dagini; Ephydrini; monophyly; taxonomy

INTRODUCTION

In 2016, Mathis and Marinoni published a taxonomic revision of the Neotropical Ephydrini Zetterstedt (Diptera: Ephydridae: Ephydrinae), mentioning that a cladistic study and analysis of this tribe were underway. This paper presents the results of that study, including a cladistic analysis of Ephydrini and a genus-level taxonomic treatment of the included taxa. In many respects, this paper is a companion paper to our recent publication on the tribe Scatellini (Costa et al. 2024), and like that paper, further contributes to Oldroyd’s (1964: 188-189) and Borkent’s (2018: 108) statements that shore flies offer excellent opportunities for studying phylogenetic relationships. We endorse these views and proffer this phylogenetic and taxonomic study of the tribe Ephydrini as partial fulfillment of their astute observations and recommendations.

Specimens of Ephydrinae are probably the most easily recognized (together with Ochthera Latreille) within the Ephy dridae and are also among the best-known of shore flies. The protruding and usually transversely arched face, lateroclinate fronto-orbital setae, and number of postsutural dorsocentral setae (3-4), easily distinguish taxa of this tribe. As such, they have attracted the attention of students in biology from various perspectives due to their peculiar morphology and unusual habitat preferences and tolerances. Species of this subfamily are associated primarily with freshwater habitats, but they also occur in the effluent of hot springs, or they are associated with maritime habitats, as well as inland saline and alkaline environments in temperate and tropical regions of the world (Foote 1995, Mathis and Zatwarnicki 1995, Mathis and Marinoni 2016).

Cresson (1930) proposed the basic concept of Ephydrinae that is still largely accepted today, although the subfamily has been revised and updated in several subsequent papers. Wirth and Stone (1956), in a key to North America genera, proposed two of the included tribes within Ephydrinae: Ephy drini and Scatellini, the former being characterized by long and straight claws and the absence of pulvilli, and Scatellini by curved and generally shorter claws and well-developed pulvilli.

Mathis (1979b) presented the first cladistic analysis of the subfamily. His phylogeny presented Ephydrinae as a monophyletic group divided into three principal lineages. Some of the genera close to Ephydrini, Paracoenia Cresson and related genera, including Austrocoenia Wirth, have curved claws and pulvilli. Thus, the tribe Scatellini, as initially proposed and characterized by Wirth and Stone (1956), is a paraphyletic group, being differentiated by plesiomorphies with the tribe Ephydrini as an included lineage within their concept of “Scatellini” (Mathis 1979b). Mathis (1982a) then proposed a new tribe, Dagini, to include a few related genera that were not easily included in previous classifications. Although the tribe Scatellini, as then characterized, was a paraphyletic group, the tribe Ephydrini continued to be recognized as originally characterized, including in the most recent world catalog (Mathis and Zatwarnicki 1995).

Zatwarnicki (1992) published a cladistic analysis and phylogeny for Ephydridae and divided the family into five subfamilies. In his paper, Zatwarnicki modified the subfamily Ephydrinae as follows: the tribe Parydrini was placed in Ephydrinae; the genus Brachydeutera Loew was included in Dagini; and Coenia Robineau-Desvoidy, Paracoenia and Notiocoenia Mathis were transferred from Scatellini to Ephydrini (Fig. 1). The monotypic subfamily Halmopotinae, first proposed by Canzoneri and Meneghini (1974) and comprising only the genus Halmopota Haliday, was also recognized as a lineage within the Ephydrini, and as such, this family-group name was synonymized under the subfamily Ephydrinae and the tribe Ephydrini. Zatwarnicki also restricted the tribe Ephydrini to 12 genera and proposed its monophyly, based on the following synapomorphies: medial portion of face setose (not Halmopota); postpronotum bearing setae; dorsocentral setae numbering 5; basal aedeagal opening modified (anterior margin thickened with a collar or dorsally overlapping the opening); gonite and phallapodeme combined (Zatwarnicki 1992).

Figure 1
Strict consensus cladogram of most parsimonious trees obtained from equal weighting parsimony searches, showing tribal relationships.

Subsequent to Zatwarnicki’s (1992) classification, other more recent modifications within Ephydrinae include Zhang et al. (2005; description of the Oriental genus Sinops in Dagini), Mathis (2008; description of two new Neotropical genera in Ephydrini: Paraephydra Mathis and Neoephydra), revision of Neotropical Ephydrini (Mathis and Marinoni 2016), and a phylogenetic analysis and classification for Scatellini (Costa et al. 2024).

Recently, Zatwarnicki (2023) substantially revised his 1992 classification, including a few modifications to the subfamily Ephydrinae. Although the tribes Ephydrini and Scatellini remained essentially unchanged, he proposed: (1) transferring Hyadinini from Lipochaetinae to Ephydrinae and (2) removing the genus Brachydeutera from Dagini and placing it in Hyadinini as the sister group of the Pelina Haliday lineage.

The tribe Ephydrini and its current phylogenetic relationships

In the classification of Ephydrinae, three groups have been described: the group Coenia plus related genera (Mathis 1979b) as the sister group of Scatella and related genera (Mathis 1979b), and a group with Paracoenia and related genera (group II; Mathis 1979b), Austrocoenia and Ephydrini. Olafsson (1991) presented a phylogeny of Ephydrinae based on genera from the western Palearctic Region. In his study, Olafsson proposed a monophyletic group without postpronotal setae and named it as the tribe Scatellini, thus moving Coenia to Ephydrini. The other genera comprising the group, Paracoenia, Austrocoenia and Coenia, were later moved to Ephydrini, leaving 13 genera in the tribe (Zatwarnicki 1992).

Through the years, the taxonomy, phylogeny, and classification of the tribe Ephydrini have undergone many modifications. These studies were usually based on limited groups of species or restricted geographic areas, never on a comprehensive, global basis, making the relationships among these genera less well understood. To clarify these relationships, we have undertaken a comprehensive phylogenetic analysis to test the monophyly of tribe Ephydrini and the tribe’s included genera and subgenera, based on morphological characters from adult males and females. A hypothesis of relationships among taxa within Ephydrini and the other tribes of Ephydrinae are discussed.

MATERIAL AND METHODS

Taxon sampling

Our study includes 30 terminal taxa (19 from the ingroup and 11 taxa as outgroups). The ingroup taxa (Ephy drini) comprise 13 genera, including three groups with subgenera and three with species groups, representing 118 known species (Mathis and Zatwarnicki 1995), all included in the matrix and analysis. The choice of a representative species for each genus was usually the type species. This selection would thereby facilitate any potential taxonomic or nomenclatural changes. The choice of outgroup taxa considered previous phylogenetic hypotheses for Ephydrinae (Mathis 1979a, 1979b, 1980, 1982a, Mathis and Simpson 1981, Olafsson 1991, Zatwarnicki 1992). The 11 outgroup exemplar species include all other tribes within the Ephydrinae. A complete list of terminal taxa is presented in ^{Appendix 1}.

The descriptive terminology, with the exceptions noted in Mathis (1986) and Mathis and Zatwarnicki (1990), follows Cumming and Wood (2017).

Most specimens used in this study are from the National Museum of Natural History, Smithsonian Institution (USNM). A few specimens were borrowed from the following institutions: American Museum of Natural History, New York, New York, USA (AMNH); Academy of Natural Sciences of Philadelphia, Pennsylvania, USA (ANSP); The Natural History Museum, London, UK (BMNH); Coleção Entomológica Padre Jesus Santiago Moure, Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil (DZUP); Hungarian Natural History Museum, Budapest, Hungary (HNHM); New Zealand Arthropod Collection, Entomology Division, Auckland, New Zealand (NZAC).

Character sampling and coding

We selected characters from the external and internal morphology of adult males and females. A survey of characters used in previous phylogenetic studies (Mathis 1979b, 1980, Olafsson 1991, Zatwarnicki 1992, Costa et al. 2024) was conducted. These characters were re-evaluated and in some cases were reinterpreted.

Character elaboration considered the following criteria: topological correspondence among the observed structures and the independence and hierarchy of characters and states (Hawkins et al. 1997). The characters were treated as hypotheses of grouping (taxic homology sensu Patterson 1982). Most characters are binary, but to preserve our interpretation of the morphological diversity, we chose to construct multi-state characters in a few cases. Contingent coding was used; the characters were coded as present or absent and, if a feature is present, the variation is coded in one or more states. The matrix data were constructed in Winclada v. 1.00.08 (Nixon 1999-2002). The character states indicated with the symbol [-] mean inapplicable states and those with the symbol [*] are polymorphisms. The complete list and description of the morphological characters are presented in ^{Appendix 2}. The character matrix is presented as ^{Supplementary Table S1}.

Cladistic analysis

The cladistic analyses were carried out using the program TNT version 1.5 no taxon limit (Goloboff and Catalano 2016). The multi-state characters were treated as non-additive under Fitch parsimony (Fitch 1971). Hyadina furva (Cresson 1926) was used to root the tree. The search was heuristic. The parameters utilized in all searches were as follows: “Max.tree” = 100,000; “random seed” = 100; “number of additional sequences” = 10,000; “tree to save per replication” = 10, utilizing “tree bisection reconnection” (TBR) as the permutation algorithm of the branches. Searches for the most parsimonious trees were conducted using two character-weighting schemes: equal weighting and implied weighting (Goloboff 1993). Heuristic searches using implied weighting were carried out using a TNT script (setk.run) written by Salvador Arias to calculate the appropriate value for the constant K (for details see Goloboff et al. 2008). The script returned a value of K = 4.375 for our data set, which was then applied to run the analysis.

Branch support was evaluated for the trees obtained under both weighting schemes. For equal weighting, Bremer support was used (Bremer 1994) while for the implied weighting analysis, symmetric resampling support was applied (Goloboff et al. 2003). The cladograms generated with TNT were then edited using Winclada version 1.00.08 (Nixon 2002). In the resulting topologies (Fig. 2: Equal weighting; Fig. 1: Implied weighting), synapomorphies unique to a specific clade, referred to as “non-homoplasious synapomorphies,” are indicated by black circles. Synapomorphies present in multiple clades, termed “homoplasious synapomorphies,” are represented by blank circles. The cladogram is the primary means to convey relationships, and the discussion that follows is simply to augment or highlight relationships.

Figure 2
Summarized tree combining the results from the most parsimonious trees obtained from implied weighting parsimony searches, showing ingroup relationships. Only unambiguous transformations are shown, and character numbers are superimposed on the branches. A and B show the differences among the two most parsimonious topologies. Solid black circles represent non-homoplasious synapomorphies and blank circles represent homoplasious synapomorphies. Symmetric resampling support is indicated below each branch in red.

RESULTS AND DISCUSSION

A total of 113 characters were examined and coded for the 30 terminal taxa, including external morphological characters, as well as those from mouthparts and male and female terminalia. The characters are arranged and listed according to their position on the body, from anterior to posterior region. Thirty-four characters are from the head, 40 from the thorax, and 39 from the abdomen.

We used both equal and implied weighting approaches, resulting in six and two most parsimonious cladograms, respectively. Both schemes produced trees with a length of 262 steps. We favored the results obtained with the implied weigh method due to its higher resolution and greater explanatory power (Farris 1983). From the implied weighting analysis, the cladograms had a consistency index (CI) of 0.48 and a retention index (RI) of 0.75. The strict consensus cladogram has one extra and unresolved node (Ephydrella/Paraephydra). Branch support is indicated on each clade branch, with values calculated from 19,640 suboptimal trees. Our discussion will focus on the relationships derived from the trees obtained through implied weighting, highlighting their differences.

Relationships among tribes of Ephydrinae

The subfamily Ephydrinae, as anticipated and demonstrated in the above-cited papers, is a well-corroborated monophyletic clade that is substantially supported by the following nine non-homoplasious synapomorphies: 17(1), ocelli arranged as an isosceles triangle; 29(1), palpus essentially parallel sided, not claviform; 30(1), distal portion of lacinia T-shaped; 43(0), postsutural supra-alar seta present; 45(0), posterior notopleural seta inserted at same level as anterior seta; 54(1), intra-alar seta present; 96(0), gonites and epandrium fused as a single structure; 107(1), female sternite as 2 sclerites; 110(0), female ventral receptacle with an operculum. The combination of these characters also strongly corroborates the inclusion of Parydra Stenhammar and Dagini as lineages within Ephydrinae, as proposed by Mathis (1979b, 1980, 1982a) and Zatwarnicki (1992). Recently, Zatwarnicki (2023) also included the tribe Hyadinini within the subfamily Ephydrinae.

Ephydrinae comprises the following genera and tribes that were included in this analysis: Brachydeutera, Parydrini, Dagini, Scatellini and Ephydrini. In the equal and implied weighting trees, Parydra aquila + Brachydeutera neotropica + Dagini appear as a clade supported by three non-homoplasious synapomorphies: 20(1), 1 lateroclinate fronto-orbital seta; 25(1), genal seta absent; 69(1), katepisternal seta short, weakly developed; and this lineage, in turn, was recovered as the sister group of the other tribes within Ephydrinae. We note, however, that Brachydeutera is currently classified in the tribe Dagini. This genus, which had been placed in Dagini by Zatwarnicki (1992), is now the sister group of Dagini in our analysis, and its status as an included genus within Dagini or perhaps as a separate tribe remains unresolved (Fig. 2). We, however, prefer making that determination after we have studied and analyzed all genus-level taxa within Parydrini and Dagini.

The tribe Ephydrini is recovered as the sister group of Scatellini in all weighting schemes. The clade that includes these two tribes is supported by three non-homoplasious synapomorphies: 6(1), face densely setulose on medial area and ventral margin; 28(3), face transversely arched; 62(1), costal vein slightly to deeply overlapping itself at subcostal break, sometimes looking like a spur; and three homoplasious synapomorphies: 5(0), facial setulae present on medial area and lower facial margin (oral margin); 23(1), subcranial cavity large, sometimes gaping; 77(1), male abdomen with only one sternite beyond sternite 4. Both Scatellini and Ephy drini are likewise well supported monophyletic lineages: Scatellini by four non-homoplasious synapomorphies: 56(1), prescutellar acrostichal seta longer than other acrostichal setae; 60(1), wing with many white spots; 89(3), aedeagus shape as a shoe-like structure; 100(0), posterodorsal arm of gonite lacking; and one homoplasious synapomorphy: 67(1), medial scutellar seta short, at most half of the length of the apical seta; and Ephydrini by four non-homoplasious synapomorphies: 37(1), propleural setulae present; 39(5), number of postsutural dorsocentral setae 4 (1+4); 40(1), proepisternum with macrosetae; 53(1), intrapostalar seta long, only slightly smaller than postalar seta; and two homoplasious synapomorphies: 38(1), number of presutural dorsocentral setae 1; 70(1), setulae present on hindcoxal strap. The characterization of Scatellini and its included taxa have remained essentially unchanged since Wirth and Stone (1956) with updates provided in Zatwarnicki (1992, 2023), Mathis and Zatwarnicki (1995), and Costa et al. (2024). The tribe Scatellini is treated more comprehensively in a companion paper to this one (Costa et al. 2024), thus, our focus will now be on the tribe Ephydrini.

The tribe Ephydrini had been hypothesized as a monophyletic group previously (Mathis and Simpson 1981, Mathis 1982a, Zatwarnicki 1992, 2023) and our analysis further substantiates these previous hypotheses. Within Ephydrini, the basal lineages form a stepwise sequence that begins with Austrocoenia and Notiocoenia.

The genera Austrocoenia and Notiocoenia in this analysis were recovered as the basal two lineages within the tribe Ephydrini. The first node gives rise to the genus Austrocoenia, which is the sister group to all remaining sublineages in the tribe. Austrocoenia is only known from Patagonia in southern Argentina. The monophyly of Austrocoenia, which is monotypic, is substantiated by nine autapomorphies: two non-homoplasious: (11(1), frons as wide as long; and 27(2), gena high (gena to eye ratio > 0.50; and seven homoplasious synapomorphies: 9(1), absence of facial row of setulae near parafacial margin; 10(2), facial projection or hump relatively higher than half height of head; 12(1), frontal vitta subquadrate; 41(0), postpronotum with 1-3 setae plus scattered setulae; 56(1), prescutellar acrostichal seta longer than other acrostichal setae; 65(0), presence of Costal vein spines along anterior margin; 106(1), female sternite 7 separated in two sclerites.

The next step or node comprises Notiocoenia, which, like Austrocoenia, is a south latitude genus from the Neotropics, being only known from southern Chile (vicinity of Osorno). The monophyly of Notiocoenia is established in our results by two non-homoplasious synapomorphies: 111(2), operculum of female ventral receptacle tiny, flat, and extended process elongate; and 112(1), operculum of female ventral receptacle not covering the extended process; and one homoplasious synapomorphy: 77(2), male without well-developed sternites after sternite 4. The sister group to Notiocoenia is defined by two non-homoplasious synapomorphies: 84(1), surstylus fused to epandrium but distinguishable as a surstylus; and 103(0), female sternite 9 bearing one pair of strong setae; and two homoplasious synapomorphies: 48(1), acrostichal setae scattered randomly, not forming rows; 104(1), female cerci bearing one long, strong, prominent seta, inserted posteroventrally; and the taxa arising from this node are the genus Coenia and its sister group, which includes all remaining genera within Ephydrini. Coenia is a Holarctic genus and its monophyly is confirmed by four homoplasious synapomorphies: 9(0), the absence of facial row of setulae near parafacial margin; 54(0), absence of intra-alar seta; 67(1), short median scutellar seta; 72(0), male forefemur with stout anteroventral seta. The sister lineage to Coenia is confirmed by one non-homoplasious synapomorphy: 36(0), the presence of prosternal setulae; and four homoplasious characters: 10(2), the relative height of facial projection or hump higher than half height of head; 27(1), the moderately high gena; 41(0), 1-3 postpronotal setae plus scattered setulae; and 68(1), the short anepisternal setae.

The next dichotomy includes the genus Paracoenia and its two subgenera: Paracoenia and Thiomyia Wirth. The branch giving rise to Paracoenia is supported by five characters, all homoplasious synapomorphies: 17(0), ocelli equally distant from each other, as an equilateral triangle; 19(2), eye conspicuously higher than wide than high; 33(0), sclerite 2 of labellum more or less as long as width of labellum; 65(0), presence of Costal vein spines along anterior margin; 80(1), male tergite 5 with posterolateral projection. The sister lineage to Paracoenia is substantiated by three homoplasious synapomorphies (12(1), subquadrate frontal vitta; 73(1), tarsal claws nearly straight; 77(2), male without well-developed sternites after sternite 4). This clade of genera comprises the tribe that Wirth and Stone (1956) initially characterized in their key as Ephydrini, and in our analysis, these are the most derived genera of the tribe (Dimecoenia Cresson, Ephydra, Ephydrella Tonnoir and Malloch, Halmopota, Neoephydra, Paraephydra, Setacera Cresson).

The next recovered node is a trisomy in the strict consensus of our implied weighting analysis, giving rise to Ephydrella, Paraephydra, and the remaining genera of the tribe that were not recovered previously. Our analyses have revealed conflicts when attempting to resolve the diversification pattern following the emergence of this clade. On the one hand, one interpretation posits character (111(1), female ventral receptacle with operculum relatively reduced, tube-like, extended process elongate, twice or longer than width of operculum) as the apomorphy that could differentiate Ephydrella and the remaining genera of the tribe from Paraephydra. On the other hand, the tree we have chosen to discuss our results, identifies character 85(1), male surstyli with anterolateral projection, as the adaptive character that could have helped differentiate Paraephydra and the remaining genera from Ephydrella.

The monophyly of Ephydrella, which only known from Australia and New Zealand, is supported by one non-homoplasious synapomorphy: 89(4), large and bulky tubular aedeagus; and one homoplasious synapomorphy: 81(0), opening of epandrium or epandrium/surstyli present. The second node in the trisomy gives rise to Paraephydra, which includes two Neotropical species. The monophyly of Paraephydra is supported by one non-homoplasious synapomorphy: 51(2), acrostichal prescutellar seta absent in males and present in females; and four homoplasious synapomorphies: 8(2), long lateral facial setae curved laterodorsally; 10(1), facial projection half height of head; 53(0), small intrapostalar seta; and 110(1), female without operculum. The third lineage of the trisomy is supported by two homoplasious characters: 9(1), absence of facial row of setulae near parafacial margin; and 84(0), surstylus fused to epandrium and distinctly separated from it.

The latter node of the trisomy results in a simple bifurcation. One of the nodes of the bifurcation gives rise to two genera: Setacera and Neoephydra, with its monophyly supported by one homoplasious synapomorphy: 81(0), opening of epandrium or epandrium/surstyli present. The monophyly of Setacera is supported by six homoplasies: 19(1), eye conspicuously wider than high; 68(0), anepisternum with a large and a small seta; 89(1), quill-like aedeagus; 103(1), slender setae on female sternite 9, indistinguishable from surrounding setae; 104(0), slender setae on female cerci, indistinguishable from surrounding setae; and 113(0), absence of larval prolegs. The sister group to Setacera is Neoephydra and the monophyly of the latter is supported by two homoplasious characters: 86(1), surstylus divided in two differentiated pieces; and 99(1), fused gonal arch and phallapodeme.

The sister group of the combined Setacera/Neoephydra lineage is the node that gives rise to a bifurcation that is supported by a single homoplasious synapomorphy: 80(1), male tergite 5 with a posterolateral projection. This node is also a trisomy branching into two genera (Ephydra and Halmopota) and one apical clade that includes Calocoenia, Cirrula Cresson and Dimecoenia. The genus Ephydra and its two subgenera (Ephydra and Halephydra Wirth) are supported and its monophyly confirmed by one non-homoplasious synapomorphy: 20(2), presence of three fronto-orbital setae. The Old-World genus Halmopota is supported by a single non-homoplasious synapomorphy: 39(6), the presence of 3(2+3) postsutural dorsocentral setae. The monophyly of the third branch, including Calocoenia, Cirrula, and Dimecoenia, is confirmed by one non-homoplasious synapomorphy: 22(1), paravertical seta long; and one homoplasious synapomorphy: 111(0), female ventral receptacle with operculum helmet-like or mushroom-like, rounded to trapezoidal, extended process not longer than width of operculum. Calocoenia and its two subgenera (Calocoenia and Leptocoenia Mathis) are supported by one homoplasious synapomorphy: 74(0), pulvilli conspicuous below each claw. Cirrula and its sister genus, Dimecoenia, are supported by one non-homoplasious synapomorphy: 13(1), interfrontal seta present. The monophyly of Dimecoenia is confirmed by one non-homoplasious synapomorphy: 113(2), secondary reduction or absence of larval prolegs.

Phylogenetic conclusions

This cladistic analysis is the most comprehensive phylogenetic assessment of the tribe Ephydrini thus far available. The taxon sampling for this study included repre sentatives of all genera, subgenera, and species groups. While we focused primarily on type species to represent each genus, we feel that the morphological and biogeographical diversities were adequately sampled.

The tribe Ephydrini, as proposed by Wirth and Stone (1956), Zatwarnicki (1992, 2023) and Mathis and Zatwarnicki (1995), was recovered as a monophyletic group, as were all included genera and subgenera. The basal two lineages in the tribe each comprise single genera, Austrocoenia and Notiocoenia, which are from austral South America. The next two nodes give rise to Coenia and Paracoenia. Each of these two genera have combined species distributions that are Holarctic. The next lineage, Paraephydra, includes two Neotropical species. The next clades comprise multiple genera from various biogeographical regions as follows: Setacera, and Ephydra, most biogeographic regions; Ephydrella, Australasian; Neoephydra, Neotropical; Calocoenia, Cirrula and Dimecoenia, mostly Nearctic (some species also occur in the very northern Neotropical Region); finally, Halmopota, primarily Palearctic.

TAXONOMY

Tribe Ephydrini Zetterstedt, 1837

118 species (+7 nomina dubia), 13 genera

Ephydrini Zetterstedt 1837: 48 (as Ephydrinae). Type genus: Ephydra Fallén 1810. - Simpson 1979: 99-107 [life histories]. - Wirth and Stone 1956: 45 [first formal use and diagnosis as a tribe]. - Olafsson 1991: 44-54 [relationships among Palearctic genera]. - Mathis and Zatwarnicki 1995: 235-254 [world catalog]. - Mathis 2008: 1-15 [key to genera]. - Lizarralde de Grosso et al. 2011: 18-22 [catalog of Argentine species]. - Mathis and Marinoni 2016: 1-110 [revision of Neotropical species].

Halmopotini Canzoneri and Meneghini 1974: 147 (as Halmopotinae). Type genus: Halmopota Haliday 1856. - Zatwarnicki 1992: 65-119 [synonymy, phylogeny, and classification].

Diagnosis. Specimens of Ephydrini may be distinguished from other Ephydridae by the following combination of character states.

Head: Mesofrons subquadrate, slightly wider posteriorly, with shiny, metallic luster; frequently with convergent, interfrontal setae inserted near anterior margin of mesofrons; dorsum of interfoveal hump usually shiny, with metallic luster, concolorous with mesofrons; fronto-orbital setae lateroclinate, two or more; face protruding, setulose to densely pilose, marginal setae larger; dorsum of interfoveal hump sometimes shiny; eye bare, usually as long as high, oval, and generally oriented obliquely to plane of epistoma; gena high, bearing a large genal seta and evenly covered with smaller setae; facial setae along oral margin usually dense and long; oral opening large, gaping, usually concealing clypeus.

Thorax: Dorsocentral setae 4-5 (1+3, 2+3), some setae sometimes weakly developed, posteriormost seta displaced laterally from alignment of anterior setae; intrapostalar seta well developed, at least equal to 1/2 length of postalar seta; postsutural supra-alar seta well developed, subequal to postalar seta; notopleuron sparsely setulose; proepisternum setulose; prosternum setose, usually more evident along posterior margin near forecoxae; anepisternum bearing one large seta near middle along posterior margin, several smaller setae or setulae may also be present; anepimeron, meron, and metapleuron bare of setae. Wing with costal vein extended to vein M₁; vein R₂₊₃ long, terminating at approximately same distance from vein R₄₊₅ as tip of vein M₁ is from vein R₄₊₅. Hindcoxal strap setose; pulvilli rudimentary or lacking; tarsal claws variable, conspicuously curved and short or shallowly curved and usually elongate.

Abdomen: Male with five visible abdominal tergites, tergite 5 distinctly trapezoidal or triangular, posterior angle bluntly to narrowly rounded or narrowly truncate; female with six, sometimes seven, visible tergites, tergite 5 subtrapezoidal, not triangular. Male terminalia: symmetrical; epandrium higher than wide, surstyli usually evident at venter of epandrium; cercal cavity and cerci relatively small (compared to many species of Scatellini); aedeagus variously shaped, usually sheathed by gonites laterally, hypandrium ventrally; phallapodeme at base of aedeagus and extended to hypandrium; subepandrial plate reduced or lacking.

Third-instar larva: Mouthhooks not joined together basally, each mouthhook spatulate and dentate marginally; anterior spiracles with 2-8 marginal papillae; posterior spiracles borne distally on bifid, retractile respiratory tube, tube 1/3-1/6 total body length; spiracular caps each bearing four spiracular openings (or series of openings), openings slit-like, oval, each bordered basally by hydrofuge interspiracular process; segments 5-12 with ventral prolegs bearing crochet-like spines in well-defined rows; dorsal patterns composed of flattened spines usually present; if prolegs and dorsal patterns absent, perhaps representing secondary developments, then spiracular openings subdivided and spiracular caps elongate.

Natural history. Larvae of most Ephydrini are easily recognized by their elongate respiratory tube, ventral prolegs, and dorsal pattern of spines. The larvae of Dimecoenia are exceptional (Mathis and Simpson 1981) in not having conspicuous prolegs but can be distinguished by the shape of their mouthparts, the unique structure of the posterior spiracles, and their habitat distribution (salt marshes).

Distribution. Taxa of Ephydrini occur in all biogeographical regions except for Antarctica, although not equally. Details are provided under each genus, subgenus, or species group.

Discussion. The monophyly of the tribe Ephydrini is well established and is based on the following synapomorphies:

1. Setal vestiture of prosternum: In members of Ephydrini, the prosternum is setulose to setose, especially ventrally and posteriorly around the coxal cavities but usually more extensively. The generalized condition in the family is for the prosternum to be bare of setulae or setae.

2. Number of dorsocentral setae: Although other genera of the subfamily Ephydrinae sometimes have five pairs of dorsocentral setae, the anterior pair (or pairs) is sometimes weakly developed. Only in members of Ephydrini are there five welldeveloped pairs (the anterior pair is presutural + four pairs of post-sutural dorsocentral seta [character 39 (5)]; specimens of Cirrula gigantea have the anterior four pairs of dorsocentral setae weakly developed, a condition we interpret to be secondary and a synapomorphy for that genus).

3. Development of intrapostalar seta: In most species of the family, the intrapostalar seta is either lacking or is very much reduced, less than onehalf the length of the postalar seta. In members of Ephydrini, the intrapostalar seta is usually as long as the postalar seta.

4. Setal vestiture of propleuron: Throughout most of the family, this pleural region is bare of setae (although frequently it is thinly to densely microtomentose). In members of this lineage, there are numerous setulae that are generally conspicuously evident.

5. Hindcoxal strap: The hindcoxa has a sclerotized strap that extends around the posterior side. This strap bears four or five setae in members of Ephydrini. Elsewhere in the family this strap is bare.

6. Pulvilli: With few exceptions in the family generally, the pulvilli are evident as conspicuous pads beneath the tarsal claws. In most genera of Ephydrini, however, the pulvilli are frequently either rudimentary or appear to be lacking.

7. Tarsal claws: The tarsal claws are more shallowly curved and are usually elongated in most genera of Ephydrini but not all. The generalized condition is for claws to have conspicuous curvature and a shorter length.

8. Larval prolegs: Except for a secondary loss in Dimecoenia, larvae of genera related to Ephydra have prominent, ventral prolegs that bear crochets. These structures are an adaptation to the algal-mat habitat of the immatures of these flies and assist in grasping and movement through the substrate. The secondary loss of prolegs in larvae of Dimecoenia has apparently occurred secondarily as the latter shifted back to a mud-shoreline habitat. Larvae of Dimecoenia have creeping welts, like those of other mud inhabiting Ephydridae (Mathis and Simpson 1981).

9. Habitat of immatures: The generalized habitat for the subfamily Ephydrinae is probably shoreline mud. This is the habitat of most species of Scatellini and Parydrini. However, members of Ephydrini have adapted to algal mats on the surface of both lentic and lotic water systems.

Although the tribe Ephydrini is a monophyletic lineage in classifications in the 20^th Century, its companion tribe, Scatellini, as that lineage was initially characterized, was paraphyletic. Ephydrini, for example, are but one among other monophyletic lineages that comprise the original cha racterization of Scatellini (history reviewed in Mathis 1979c, 1980). In a recent and companion study, the tribe Scatellini was recovered as a monophyletic lineage, as that tribe is now characterized and with its component sublineages (Costa et al. 2024). These studies follow a precedent first established by Zatwarnicki (1992, 2023) and Mathis and Zatwarnicki (1995).

Key to genera and subgenera of Ephydrini

1. Head with clypeus prominent, greatly exposed below oral margin .................... Halmopota Haliday

1’. Head with clypeus largely retracted into oral cavity, at most barely exposed .................... 2

2. Thorax with prosternum setulose on at least posterior portion. Pulvilli much reduced or absent; tarsal claws long and nearly straight .................... 3

2’. Thorax with prosternum bare. Pulvilli well developed; tarsal claws short and distinctly curved .................... 12

3. Antenna with basal flagellomere bearing a large late ral seta just below insertion of arista .................... Setacera Cresson

3’. Antenna with basal flagellomere without a lateral seta .................... 4

4. Head with 3 or more well-developed fronto-orbital setae. Anterior presutural supra-alar seta usually well developed, subequal to notopleural setae .................... 5

4’. Head with 2 well-developed fronto-orbital setae present. Anterior presutural supra-alar seta absent or much reduced, much smaller than posterior notopleural seta .................... 8

5. Head with 5-6 well-developed fronto-orbital setae .................... Neoephydra Mathis (in part)

5’. Head with 3-4 well-developed fronto-orbital setae (Genus Ephydra Fallén) .................... 6

6. Thorax with 2 presutural dorsocentral setae, anterior seta sometimes rather short. Face very thickly setulose; arista short, weakly haired, thicker on its basal half; usually 2 posteriorly directed rows of well-developed cruciate interfrontal setae present, with these rows closer to orbital setae than to each other. Male with basitarsomere of foreleg bearing ventral tuft of long setulae near tip .................... Ephydra (Hydropyrus) Cresson

6’. Thorax with 1 presutural dorsocentral seta. Face with 1 well-developed row of facial setae and 1 of oral setae, otherwise thinly short-haired; arista without markedly swollen basal region; usually not more than 1 pair of interfrontal setae situated as close to each other as to orbital setae. Male with basitarsomere of foreleg without ventral tuft of setulae .................... 7

7. Head with 1 well-developed interfrontal seta present; palpus well developed. Crossvein dm-m making nearly a right angle with vein M_l .................... Ephydra (Ephydra) Fallén

7’. Head with interfrontal seta weak or absent; palpus small. Crossvein dm-m forming an acute angle with vein M_l. .................... Ephydra (Halephydra) Wirth

8. Head with cruciate interfrontal setae present .................... 9

8’. Head with cruciate interfrontal setae absent .................... 11

9. Thorax with dorsocentral setae 4 (1+3). Arista bearing subpectinate dorsally branching rays on basal 1/2 .................... Paraephydra Mathis

9’. Thorax with dorsocentral setae 5 (1+4). Arista at most minutely haired on basal 1/2 .................... 10

10. Aristal rays long, length subequal to width of pedicel. Hindfemur of male not differing markedly from fore- or midfemur, lacking stout setae as above; hindtibia of male lacking tuft of setulae; hindtarsi of male cylindrical, normal .................... Dimecoenia Cresson

10’. Aristal rays short, length approximately 1/2 width of pedicel. Hindfemur of male conspicuously swollen, bearing short row of 4-5 stout setae along anteroventral surface toward base; hindtibia of male with ventroapical tuft of setulae; hindtarsi of male variously modified .................... Cirrula Cresson

11. Thorax with a well-developed prescutellar acrostichal seta; 2 postpronotal setae, dorsal seta about 1/2 length of ventral seta; prosternal setulae sparse (Australasian) .................... Ephydrella Tonnoir and Malloch

11’. Thorax lacking a well-developed prescutellar acrostichal seta; 1 postpronotal seta; prosternal setulae numerous (Neotropical) .................... Neoephydra Mathis (in part)

12. Thorax with dorsocentral setae 4 (1+3); postpronotal seta(e) either weak, at most 1/4 length of posterior notopleural seta, or lacking. Hindcoxa bare posteriorly .................... 13

12’. Thorax with dorsocentral setae 5 (1+4) (anterior setae reduced in Austrocoenia); postpronotal seta distinct, at least 1/2 as long as posterior notopleural seta. Hindcoxa bare or with a row of setae posteriorly .................... 14

13. Antenna with arista bearing long hair-like rays dorsally, length of longest rays subequal to height of basal flagellomere; frons only moderately to sparsely microtomentose, especially subshiny mesofrons (Holarctic) .................... Coenia Robineau-Desvoidy

13’. Antenna with arista either almost bare or bearing short hair-like rays dorsally, length of longest rays about 1/2 height of basal flagellomere; frons uniformly and densely microtomentose, dull, mesofrons little differentiated from parafrons (Neotropical) .................... Notiocoenia Mathis (in part)

14. Head with paravertical seta large, at least 1/3 length of medial vertical seta .................... 15

14’. Head with paravertical seta small, generally subequal to setae of postocular row .................... 18

15. Wing with R stem vein bearing 1-2 setulae dorsally, inserted beyond transverse septum. Scutellar disc convex. Hindcoxa with row of setae along posteroventral margin (Genus Paracoenia Cresson) .................... 16

15‘. Wing with R stem vein bare dorsally. Scutellar disc almost flat. Hindcoxa bare posteriorly along ventral margin (Genus Calocoenia Mathis) .................... 17

16. Thorax with both supra-alar and katepisternal setae either lacking or much reduced; midfemur of male lacking row of closely set setae along posteroventral surface; apical 4 tarsomeres explanate and short; pulvilli lacking; basal flagellomere short, less than length of pedicel; general coloration black .................... Paracoenia (Thiomyia) Wirth

16’. Thorax with both supra-alar and katepisternal setae well developed; middle femur of male with row of closely set setae along posteroventral surface; apical tarsomeres normally developed, cylindrical; pulvilli evident; third antennal segment longer than second; general coloration olivaceous gray to dark green or bluish green .................... Paracoenia (Paracoenia) Cresson

17. Larger species, body length over 3.25 mm. Gena-to-eye ratio 0.25 or larger. Costal setulae well developed, projected obliquely anteriad from ventral and dorsal surfaces .................... Calocoenia (Calocoenia) Mathis

17’. Smaller species, body length under 2.75 mm. Gena-to-eye ratio 0.20 or smaller. Costal setulae weakly develo ped, only on dorsal surface .................... Calocoenia (Leptocoenia) Mathis

18. Head with frons mostly lacking setulae and with coloration and vestiture generally uniform, microtomentose, dull; arista long, nearly double length of basal flagellomere. 1 interalar seta inserted just posterior of transverse suture .................... Notiocoenia Mathis (in part)

18’. Head with mesofrons conspicuously setulose, especially laterally, tan to brown, generally distinct from grayer parafrons, microtomentum denser; arista short, subequal to length of basal flagellomere. Interalar seta lacking .................... Austrocoenia Wirth

Generic and subgeneric treatments

Austrocoenia Wirth, 1970

Figs 3-9

AustrocoeniaWirth 1970: 3 (feminine; type species: Austrocoenia aczeliWirth 1970, original designation). - Mathis 1980: 4-7 [revision]. - Lizarralde de Grosso 1989: 59 [fauna of Argentina]. - Mathis and Zatwarnicki 1995: 235 [world catalog].

Diagnosis. Austrocoenia is distinguished from other genera of Ephydrini by the following combination of characters: Medium-sized to large shore flies, body length 3.65-5.10 mm; coloration generally gray; wing mostly hyaline; setae generally reduced.

Figures 3-9
Austrocoenia aczeli. (3) male habitus; (4) head anterior; (5) head lateral; (6) thorax dorsal; (7) epandrium and cerci posterior; (8) male terminalia lateral; (9) ventral receptacle lateral.

Head: Mesofrons conspicuously setulose, completely microtomentose, dull, lacking large setae, cruciate or otherwise, parafrons more sparsely microtomentose; lateroclinate fronto-orbital setae 2; medial and lateral vertical setae both well developed; paravertical setae either reduced or lacking; antenna short; basal flagellomere lacking a lateral seta; basal flagellomere subequal in length to that of pedicel from dorsal view; arista short, only slightly longer than length of basal flagellomere, basal 2/3 thickened; antennal grooves deeply impressed; face long, distinctly protuberant anteriorly; facial setae small, setula-like; eye subspherical, slightly higher than wide; gena mostly bare, lacking a prominent seta, high, gena-to-eye ratio at least 0.60; maxillary palpus well developed.

Thorax: Acrostichal setae in two rows, these extended posteriorly to base of scutellum, a well-developed prescutellar pair, these inserted slightly laterad of alignment of anterior setulae, rows of setulae slightly more divergent posteriorly; dorsocentral setae 5 (1:4), 1 well-developed dorso central seta inserted near base of scutellum, with 3-4 larger setae along dorsocentral tract, anterior setae more weakly developed; postpronotal setae 1-2, these subequal in length to presutural supra-alar seta; postsutural supra-alar seta reduced or lacking; disc of scutellum bare; lateral scutellar setae 2; prosternum bare. Wing normally developed, mostly hyaline; costal margin with short spinelike setae between 2^nd costal break and the apex of vein R₂₊₃; costal vein long, extended to vein M₁; R stem vein bare dorsally; costal vein ratio 0.18, M₁ vein ratio 0.78. Pulvilli well developed; tarsal claws short and distinctly curved; hindfemur of male not differing markedly from fore- or midfemur, lacking stout, closely set setae; hindtibia of male lacking tuft of setulae; hindtarsi of male evenly cylindrical, normal.

Abdomen: Tergites generally setose, setae along margins larger. Males with five visible segments, with tergite 5 longest, trapezoidal, broadly truncate posteriorly; females with 7 segments, sternites narrow, bearing robust and long setae on subanal plate. Male terminalia: Cercus of male terminalia very elongate, length equal to width of epandrium at midheight, fused ventrolaterally with epandrium; surstylus evidently fused with ventral margin of epandrium; gonite plate-like; aedeagus greatly reduced. Female terminalia: Female ventral receptacle with operculum subtrapezoidal, asymmetrical, extended process more or less C-shaped.

Distribution. Neotropical: Austrocoenia is endemic to southern South America on the Atlantic Ocean side (Patagonia, between 49°-52°S).

Remarks. Austrocoenia is a monotypic genus and is somewhat of an anomaly due to the autapomorphic condition of several of its characters.

In our morphological studies (Wirth 1970, Mathis 1980) and in this phylogenetic analysis, Austrocoenia was recovered at the base of the cladogram of Ephydrini. We further highlight that the next node in Ephydrini after Austrocoenia is the lineage giving rise to Notiocoenia, a genus that is likewise found only in the southern latitudes of South America (Chile).

Wirth (1970: 6-7) was perplexed by his new genus, noting that although Austrocoenia is clearly a member of the subfamily Ephydrinae, “...it is not closely allied with any known genus. It appears to be closest to Coenia Robineau-Desvoidy, a Holarctic genus, which it resembles to a slight extent in the presence of four pairs of dorsocentral setae and curved tarsal claws. Otherwise, its similarities are diverse and rather remote. Austrocoenia is doubtless an annectant form surviving and modified from a very early offshoot of the Ephydrinae.” The single included species, A. aczeli Wirth, is only known from the southern temperate regions of the Neotropics (Argentina, Chile). Immature stages are unknown.

Calocoenia Mathis, 1975

Figs 10-15

CalocoeniaMathis 1975: 78 (feminine; as a subgenus of Paracoenia; feminine; type species: Paracoenia platypeltaCresson 1935, original designation). - Mathis 1980: 7 [revised status]. - Mathis and Zatwarnicki 1995: 235-236 [world catalog].

Diagnosis. Specimens of Calocoenia closely resemble those of Paracoenia but may be distinguished from the latter and other genera of Ephydrini by the following combination of character states: Generally dark colored.

Figures 10-15
Calocoenia. Calocoenia paurosoma, (10) head anterior; (11) head lateral; (12) thorax dorsal. Calocoenia platypelta, (13) head anterior; (14) head lateral; (15) thorax dorsal.

Head: Mesofrons subshiny to shiny, inconspicuously setulose; 2 large, lateroclinate fronto-orbital setae; medial and lateral vertical setae both well developed; paravertical seta well developed, about half length of cruciate vertical seta. Arista pectinate, dorsally branching rays subequal to half the length of cruciate vertical seta; arista pectinate, dorsally branching rays subequal to half width of basal flagel lomere. Face with interfoveal carina, but dorsal crease not as distinct as in specimens of Paracoenia. Eye subspherical to sub-elliptical, oriented at slight oblique angle to general plane of head.

Thorax: Acrostichal setulae uniformly small, in 2 rows that extend to base of scutellum; 5 (1+4) well-developed dorsocentral setae; postpronotum with 2-3 larger setae; postsutural supra-alar seta well developed, subequal to anterolateral postalar seta; scutellar disc almost flat; prosternum bare. Costal margin with evenly spaced spine-like setae distinct from remaining setae; R stem vein bare. Hindcoxa bare posteriorly along ventral margin; with dorsum subplanate; pulvilli well developed; tarsal claws short and distinctly curved.

Abdomen: Male tergite 5 slightly wider than long; tergites generally unicolorous. Male terminalia: Surstyli as angulate processes extended from ventral margin of epandrium, contiguous medially; aedeagus well developed, acutely pointed apically. Female abdomen: Female ventral receptacle with small operculum, conformation subtrapezoidal in lateral view, extended process much longer than width of operculum.

Distribution. See under each subgenus.

Remarks. Although first described as a subgenus within Paracoenia (Mathis 1975), this taxon was later accorded generic status, as it was recovered as the sister group to the combined Paracoenia/Thiomyia lineage and not as a lineage from within Paracoenia (Mathis 1980: 7-8).

Subgenus Calocoenia Mathis, 1975

Figs 13-15

CalocoeniaMathis 1975: 78 (feminine; as a subgenus of Paracoenia; type species: Paracoenia platypeltaCresson 1935, original designation). - Mathis 1980: 7 [revised status]. - Mathis and Zatwarnicki 1995: 235 [world catalog].

Diagnosis. Although similar to Paracoenia s. str. and Leptocoenia, Calocoenia may be distinguished from either as follows: Body length 3.4-4.0 mm; subshiny to shiny, metallic brown to greenish-brown; microtomentose, gray ventrally.

Head: Mesofrons shining, bronze-gold metallic reflections; pectinate branches of arista not more than twice aristal width at base; pruinose face tan; interfoveal hump not as prominent as Paracoenia s. str., dorsally sloping; eye large, subcircular, width in profile double the length of projecting face in profile; gena-to-eye ratio 0.25; width-to-height ratio 0.66; height-to-length ratio 0.90. Chaetotaxy of head and thorax like Paracoenia s. str. except acrostichal hairs.

Thorax: Acrostichal setulae in 2 rows; dorsum microtomentum to subshiny; 5 (1+4) well-developed dorsocentral setae; scutellum flattened; pleural areas concolorous with mesonotum centrally, becoming microtomentum, grayed marginally, halters yellow. Wings with costal setae on dorsal and ventral margins; costal vein ratio 0.20; M₁ vein ratio less than 0.80. Male midfemur without comb of setulae.

Abdomen: Generally uniform, concolorous; male tergites more noticeably narrowed apically; subshiny to shiny, brown metallic reflections; tergite 5 of male more or less truncate, without anteroventral process; sternite 5 with three posteriorly oriented prongs. Male terminalia: Symmetrical; epandrium subelliptical with closely fused surstyli ventrally and a medial groove; surstylus broadly attached to ventral margin of epandrium, approximate medially, shallowly bifurcate apically with small medial process and larger lateral process; aedeagus elongate, narrow, tapered to acutely pointed, curved apex; phallapodeme robustly crescent shaped in lateral view; gonite with apical half similar to apex of aedeagus in lateral view, tapered, curved, acutely pointed. Female abdomen: Female ventral receptacle with operculum wider than high, extended process considerably longer than operculum.

Distribution. Nearctic: Temperate western Nearctic Region from Alberta in Canada south through California and New Mexico.

Remarks. Calocoenia s. str. is a monotypic subgenus that only occurs in western North America within temperate zones. We know nothing about the natural history of this species or its immature stages.

Subgenus Leptocoenia Mathis, 1975

Figs 10-12

LeptocoeniaMathis 1975: 81 (feminine; type species: Coenia paurosomaSturtevant and Wheeler 1954, original designation). - Mathis and Zatwarnicki 1995: 236 [world catalog]. - Zatwarnicki and Kahanpää 2014: 344 [Finland].

Diagnosis. Specimens of Leptocoenia closely resemble those of Calocoenia s. str. and Paracoenia but may be distinguished from the latter and other genera of Ephydrini by the following combination of character states: Moderately small shore flies, body length 2.1-2.6 mm; generally dark brown, microtomentose.

Head: Fronto-orbital areas, mesofrons nearly concolorous, the later subshiny; pectinate aristal branches at most 2.5X aristal width at base; interfoveal hump not prominent, without pronounced dorsal indentation; microtomentose face light tan; longest setae along ventral margin of face approximately 3/4 length of interfoveal hump height; genal seta weak, subequal to humeral setae. Gena-to-eye ratio 0.175; width-to-height ratio 1.00-0.65; height-to-length ratio 0.93; eye-width-to-face-length ratio 0.30.

Thorax: Mesonotum sparsely microtomentose; scutellum partially flat; acrostichal setae in two rows; 4 (1+3) well-developed dorsocentral setae; postpronotal setae present; halteres yellowish-brown to brown. Costal setae weak, developed only on dorsal margin; costal vein ratio 0.18-0.20; M₁ vein ratio 0.63-0.65. Posteroventral surface of midfemur not bearing a row of comb-like setae.

Abdomen: Ventral margin of male tergite 5 not produced as a lobe. Male terminalia: Surstylus well separated apically with a small medial triangular process between surstyli comparable to structure in Paracoenia s. str. (triangular process in Paracoenia s. str. better developed in comparison with surstyli); aedeagus generally L-shaped, robust, apically tapered to acute point; phallapodeme in lateral view hemispherical; gonite narrow, with a small, shallow, subapical projection, apex curved anteriorly, pointed. Female abdomen: Female ventral receptacle with small operculum, helmet-like, extended process three times longer than opercular height.

Distribution. The only known species, C. paurosoma, has a disjunct Holarctic distribution, occurring in the western and temperate Nearctic Region (Alberta in Canada south through Wyoming and Colorado) but also in Finland and Sweden in the western Palearctic Region. We suggest that this distribution may be the result of sampling error, i.e., a lack of sampling of potential habitats between these vastly disjunct areas.

Remarks. Leptocoenia, like the subgenus Calocoenia, is a monotypic subgenus, and it too would be an excellent candidate for molecular analysis to respond better to questions such as: (1) Are the two disjunct areas genetically as well as morphologically related? (2) Is the current status of the subgenus within Calocoenia validated?

Cirrula Cresson, 1915

Figs 16-23

CirrulaCresson 1915: 70 (feminine; type species: Cirrula gigantea Cresson, by monotypy). - Sturtevant and Wheeler 1954: 162-163 [review]. - Wirth 1965: 753 [Neotropical catalog]. - Mathis and Simpson 1981: 8-29 [revision of North American species, natural history]. - Mathis and Zatwarnicki 1995: 236-237 [world catalog].

PogonephydraHendel 1917: 42 [type species: Pogonephydra chalybea Hendel (= C. gigantea), by monotypy] [Synonymy by Hendel 1931: 10].

HydropyrusCresson 1934: 216 [type species: Ephydra hians Say, by original designation and monotypy]. - Sturtevant and Wheeler 1954: 171 [review; as subgenus of Ephydra]. - Wirth 1965: 753 [Nearctic catalog]; 1971: 374-376 [review, figures of male terminalia; as subgenus of Ephydra]. - Mathis and Zatwarnicki 1995: 236 [synonymy].

Diagnosis. Cirrula is distinguished from other genera of Ephydrini by the following characters: Moderately large to large shore flies, body length 4.83-8.52 mm.

Figures 16-23
Cirrula. Cirrula hians, (16) head anterior; (17) head lateral; (18) thorax dorsal. Cirrula austrina, (19) thorax dorsal; (20) hind leg anterior; (21) male terminalia lateral; (22) male surstyli posterior; (23) ventral receptacle lateral.

Head: Cruciate, interfrontal setae 1-2 pairs, size gene rally subequal to fronto-orbital setae (weakly developed in C. gigantea, especially females); lateroclinate, fronto-orbital setae either 2 or 3-4 pairs, slightly divergent, if two, then dorsocentral setae (1+4), if 3-4, then dorsocentral setae (2+4); antenna simple, lacking secondary seta inserted on lateral surface just below arista; arista bare to macropubescent; face uniformly setose with marginal setae larger, declinate, one species with patches of long setae above middle height of face on anterior surface of interfoveal hump.

Thorax: Prescutellar, acrostichal setae variable; dorsocentral setae 5-6 pairs (5 (1+4) in specimens with two fronto-orbital setae, 6 (2+4) in specimens with 3-4 fronto-orbital setae), well developed in Neotropical species; supra-alar seta present; presutural supra-alar seta variable; intrapostalar seta well developed. Costal vein ratio 0.18-0.19; M₁ vein ratio 0.95-1.10. Legs sexually dimorphic; hindtibia lacking apical, long seta; pulvilli greatly reduced or essentially absent; tarsal claws long and nearly straight.

Abdomen: Male terminalia symmetrical; surstyli complex, situated at ventral apex of epandrium, covering other internal structures in repose, fused medially; phallapodeme more or less C-shaped with a dorsal lobe extended far into epandrial cavity; aedeagus generally simple except in males of C. austrina, where trilobate process arises at anterior base of aedeagus. Female ventral receptacle with large operculum, generally as high as wide; extended process J-shaped, length about as long as height of operculum; conformation of receptacle in females of D. spinosa exceptional, operculum trapezoidal and much smaller, extended process three times as long as operculum length.

Third-instar larva: Prolegs distinct, better developed than those of Ephydra species; segment 3 of third-instar larvae with distinctive transverse band on venter.

Natural History: Mathis and Simpson (1981) published a detailed report on the natural history of C. austrina (Coquillett). They successfully reared specimens from several loca lities along the coast of Virginia and noted that immatures and adults reached their highest densities where the habitat was partially dried, leaving algal mats on firm ground. Adults were collected commonly by sweeping over these mats.

Unlike the larvae of Dimecoenia spinosa, those of C. austrina have eight pairs of well-developed prolegs and the third-instar larva also has a dark transverse strap at the anteroventral margin of segment three.

Aldrich (1912) and Hutchinson (1937) provided excellent and detailed accounts of the biology of the so-called “alkali-fly,” C. hians (Say). The larvae are usually found on the bottom of the water in pools of water where they feed and do not come to the surface. The puparia attach to any available object. In storms, the puparia detach and form wind rows along the shore.

Distribution. New World. Primarily the temperate western region of the Nearctic Region but with a southward extension into the northern Neotropical Region (Belize (Stann Creek District)).

Remarks. Cirrula now comprises four species (C. austrina (Coquillett), C. currani (Wirth), C. gigantea Cresson, and C. hians (Say)) and is similar and closely related to the genus Dimecoenia.

Coenia Robineau-Desvoidy, 1830

Figs 24-26

CoeniaRobineau-Desvoidy 1830: 800 (feminine; type species: Coenia caricicola Robineau-Desvoidy 1830 (= Ephydra palustris Fallén 1823), monotypy). - Mathis 1975: 82-84 [revision of Nearctic species]. - Mathis and Zatwarnicki 1995: 237-238 [world catalog]. - Krivosheina 2001: 1367-1371 [review of Palearctic species].

Caenia, error for Coenia. - Walker 1853: 259 [unjustified emendation]. - Loew 1860: 38 [European Ephydridae]. - Becker 1896: 207 [Palearctic fauna]; 1905: 214 [Palearctic catalog].

Diagnosis. Coenia is distinguished from other genera of Ephydrini by the following combination of characters: Moderately small shore flies, body length 2.20-2.80 mm.

Figures 24-30
Coenia and Dimecoenia. Coenia palustris, (24) head anterior; (25) head lateral; (26) thorax dorsal. Dimecoenia spinosa, (27) head anterior; (28) head lateral; (29) thorax dorsal; (30) hind leg anterior.

Head: Frons much wider than high, only moderately to sparsely microtomentose, especially subshiny mesofrons; no cruciate interfrontal setae; two well developed fronto-orbital setae; paravertical setae weakly developed, not subequal to vertical setae. Arista bearing long rays dorsally on basal 3/4, length of longest rays subequal to height of basal flagellomere. Face with lateral margins and oral margin bearing long setae, otherwise setulose, although medial area with setae shorter than marginal setae. Gena short, about half height of basal flagellomere; genal seta well developed.

Thorax: Mesonotum generally dark colored, blackish brown; scutellum triangular, posterior angle rounded; no well-developed prescutellar acrostichal pair of setae; 4 (1+3) well-developed dorsocentral setae; postpronotal seta(e) either weak, at most 1/4 length of posterior notopleural seta, or lacking; 1 presutural supra-alar seta; 1 supra-alar seta; 1 postalar seta; prosternum bare; 2 scutellar setae; 2 notopleural setae; 1 large anepisternal seta; 1 well developed katepisternal seta. Costal vein ratio 0.21-0.22; M₁ vein ratio 0.66-0.69. Hindcoxa bare posteriorly; pulvilli well developed; tarsal claws short and distinctly curved.

Abdomen: Male with five visible tergites dorsally, sternite 5 longer than wide, triangular. Male terminalia: Surstylar bases adjacent, separated by a narrow groove, or fused, apically separated as surstylar arms, arms pointed or digitiform, sometimes irregularly; gonite moderately well developed, elongate, regularly to irregularly tapered to acute apex; aedeagus elongate, moderately thin to very thin, shallowly to conspicuously curved, tapered from base to apex, apex acutely pointed; phallapodeme short to elongate, shallowly to conspicuously curved, thin to moderately thick medially, if thick tapered toward apices, distinct keel not evident. Female abdomen: Female ventral receptacle with small operculum, helmet-like, extended process three times longer than opercular height, C-shaped with short dorsal extension into operculum.

Third-instar larva (based on Foote 1990): Small, body length 7.60 mm; elongate, nearly cylindrical, legless but with creeping welts; integument bearing slightly pigmented scales of similar shape, scales not forming patterns on dorsal surface; with circles of pigmented scales on thoracic segments, abdominal segments fully covered in scales; two types of sensilla: rayed and rosette-like (peg-like); pseudocephalon bilobed; antennae two-segmented; oral papillae comb-like; mouth brushes a long, fluffy comb at distal end; tips of oral hooks highly dentate; anterior spiracles with 4-6 finger-like projections; retractable respiratory tube branched at middle with two fleshy protrusions; anal opening smooth, transversely elongated.

Natural history: Krivosheina (2001: 1367) wrote that larvae feed on detritus and that adults are found at sites with stagnant water during the summer. Foote (1990) suggested that there can be as many as 9-12 generations during the summer season.

Distribution. The composite distribution for species of Coenia is Holarctic with six of seven species occurring in the Palearctic Region. Most species have relatively small distributions geographically with five species (C. caucasica Krivosheina, C. deserta Krivosheina, C. elbergi Dahl, C. palustris (Fallén), C. vulgata Krivosheina) being found thus far only in the Palearctic Region, and one species (C. alpina Mathis) being exclusive to the Nearctic Region. Only C. curvicauda (Meigen) is more widespread, having a Holarctic distribution. Most species occur at higher latitudes with only C. palustris ranging southward to the Azores and Canary Islands in the Old World.

Remarks. The most recent revisions are Mathis (1975) for the Nearctic species and Krivosheina (2001) for the Palearctic species. Like some other genera of Ephydrini, specimens of Coenia are not commonly collected and are thus poorly represented in collections.

Dimecoenia Cresson, 1916

Figs 27-30

DimecoeniaCresson 1916: 152 (feminine; type species: Coenia spinosa Loew, by original designation). - Sturtevant and Wheeler 1954: 166 [review, in part]. - Wirth and Stone 1956: 472 [review in part, species of California]. - Wirth 1965: 755 [Nearctic catalog]. - Steyskal 1970: 462-465 [review in part, figures of male and female terminalia]. - Mathis and Simpson 1981: 29 [revision of North American species, natural history]. - Mathis and Zatwarnicki 1995: 238-240 [world catalog].

Diagnosis. Dimecoenia is distinguished from other gene ra of the tribe Ephydrini by the following combination of characters: Moderately large to large shore flies, body length 4.25-6.15 mm; mostly dull, olivaceous brown to grayish brown, dorsum with some subshiny to shiny areas dorsally.

Head: Frons with shiny, submetallic mesofrons, parafrons dark but not shiny. one pair of well-developed cruciate interfrontal setae; two well-developed lateroclinate fronto-orbital setae, slightly divergent; paravertical setae small; both medial and lateral vertical setae well developed. Basal flagellomere simple, lacking secondary seta inserted laterally just below arista; arista tapered gradually from thickened base to style-like apex, approximately basal 2/3 with dorsal, hair-like rays, thereafter bare, aristal rays nearly as long as width of pedicel. Facial hump poorly developed, shallowly projected, dorsal portion of hump with some shiny metallic coloration; ventral margin of antennal grooves nearly hori zontal, not sloping ventrally at conspicuous angle; facial setae best developed along lateral and oral margins; one large genal seta. Gena relatively short, height about equal to height of basal flagellomere.

Thorax: Chaetotaxy: Acrostichal area with setulae only, no well-developed prescutellar pair; 5 (1+4) dorsocentral setae, posterior seta displaced laterally; 1 presutural supra-alar seta; 1 supra-alar seta; postpronotum with 1 large seta and a smaller seta; 1 postalar seta; 2 lateral scutellar setae; prosternal setulae sparse on at least posterior portion; anepisternum with 1 long seta; katepisternum with 1 long, dorsoclinate seta. Wing generally hyaline; dorsal costagial seta subequal in length to anteroventral costagial seta; costa with numerous, conspicuous, spine-like setulae; legs of both sexes similar; costal vein ratio 0.24-0.26; M₁ vein ratio 0.81-0.85. Tarsal claws long and nearly straight; pulvilli greatly reduced or essentially absent.

Abdomen: Generally subshiny; anterior portion of each tergite dark brown posterior portion lighter, grayish green; male tergite 5 as long as wide, longer than tergite 4. Male terminalia: Epandrium more or less oval in posterior view, anteroventral margin evenly rounded; surstyli with large medial flange and posterolateral, slender processes; gonite 4X longer than wide, anteroventral margin broadly and shallowly U-shaped; phallapodeme with posteromedial broad keel; aedeagus a simple tube, mostly parallel-sided. Female terminalia: Female ventral receptacle with operculum much smaller than extended process, trapezoidal; extended process broadly curved, widest medially.

Third-instar larva: Larvae lacking well-developed prolegs on segments other than segment 12, only a short, bump-like process evident.

Natural history: Larvae of Dimecoenia represent an apparent reversal in the generalized adaptive scheme of Ephydrini by inhabiting mud substrates associated with salt marshes. This has apparently resulted in the atrophy of the prominent, ventral prolegs, including the crochets, which are functionally adapted to movement within algal mats.

Distribution. The composite distribution for the two species now included in Dimecoenia, D. fuscifemur Steyskal and D. spinosa (Loew), is temperate North America with specimens of D. spinosa occurring southward to Costa Rica and on some islands of the West Indies.

Remarks. As characterized here, Dimecoenia now includes just two species, and these were most recently revised by Mathis and Simpson (1981). The monophyly of this clade is confirmed by the following synapomorphies: 1. The anterior margin bearing conspicuous, spine-like setae; 2. Ventral margin of antennal facial groves rounded, nearly horizontal and not steeply angled.

Ephydra Fallén, 1810

EphydraFallén 1810: 22 (feminine; type species: Ephydra riparia Fallén, by subsequent designation [Curtis 1832: plate 413]). - Wirth 1968: 22 [catalog of South American species]; 1971: 357-377 [review of New World species, figures of male terminalia]; 1975: 11-44 [revision of Old World species]. - Zack et al. 1976: 205 [spatial isolation of species]. - Cash-Clark and Bradley 1994: 309-318 [larva of E. hians]. - Mathis and Zatwarnicki 1995: 240-247 [world catalog]. - Mathis and Marinoni 2016: 88-97 [revision of Neotropical species]. - Krivosheina and Ozerov 2021: 345-360 [Russian fauna]. - Yakovleva et al. 2024: 360-375 [biology and immature stages of E. riparia].

Diagnosis. Ephydra is distinguished from other genera of Ephydrini by the following characters:

Head: Lateroclinate, fronto-orbital setae 3, well develo ped, subequal; development of cruciate, interfrontal setae variable, either with one well-developed pair or weak to lacking; basal flagellomere simple, lacking secondary seta inserted below arista on lateral surface; arista variable, subpectinate to macropubescent, if subpectinate, basal thickening extended about 1/3 of aristal length, if macropubescent, basal thickening extended over 1/2 of aristal length; antennal groove distinct but not deeply impressed.

Thorax: 5 (1+4) well-developed; dorsocentral setae; presutural supra-alar seta present; intrapostalar seta pre sent; supra-alar seta present; disc of scutellum generally concolorous with posterior portion of scutum. Costal vein ratio 0.24-0.40; M₁ vein ratio 0.61-0.81. Tarsal claws long, although length variable, and nearly straight; pulvilli greatly reduced or absent.

Abdomen: Structures of male terminalia considerably modified depending on subgenus and species group (see appropriate diagnosis of subtaxon for further details). Female terminalia: Female ventral receptacle with operculum small, trapezoidal in shape; extended process relatively large, C-shaped, length 2-3 times width of operculum.

Distribution. This speciose genus occurs primarily in temperate regions of the world as follows: New World. Widespread mostly in the Nearctic Region but extended into the northern Neotropical Region (12°-65°N): Canada (just south of the Great Bear Lake), southward into Mexico (Oaxaca) and the West Indies (Dutch West Indies). Old World. Widespread, mostly in the Palearctic and Afrotropical (temperate) regions but extended into the northern Oriental Region: Norway to Japan, southward to the Canary Islands, South Africa, across southern Asia (Afghanistan, Iran, and Tibet) to Japan and China.

Remarks. Wirth (1971, 1975) published excellent revisions of Ephydra on a worldwide basis, and his two papers should be consulted for a more detailed discussion of the natural history and for identification of extralimital species. Our treatment is essentially a synopsis of Wirth’s valuable studies, although with some modifications. Krivosheina and Ozerov (2021) recently produced an excellent review of the Russian fauna. Ephydra is the most speciose genus in the tribe Ephydrini with 34 species, and these are classified into two subgenera, Ephydra and Halephydra. The subgenus Ephydra is further divided into species groups. The subgene ra and species groups are characterized and identified in the following key.

Key to subgenera and species groups of Ephydra

1. Cruciate interfrontal setae weak or lacking; crossvein dm-m forming an acute angle with vein M₁; palpus small; coloration of mesonotum strongly whitish gray (subgenus Halephydra Wirth) .................... E. gracilis Packard

1’. One pair of well-developed, cruciate, interfrontal setae; crossvein dm-m forming nearly right angle with vein M₁; palpus well developed; coloration of mesonotum shiny to moderately grayish (subgenus Ephydra Fallén) .................... 2

2. Anterior acrostichal setae in 2 distinct rows; coloration generally grayish, microtomentose; tarsal claws generally nearly as long as tarsomere 5; male aedeagus nearly straight, lacking recurved, basal process .................... glauca Group

2’. Anterior acrostichal setae unseriated or in 4-5 irregu lar rows; coloration generally olive green, microtomentose; tarsal claws generally not more than half as long as tarsomere 5; male aedeagus with strongly recurved basal process .................... riparia Group

Subgenus Ephydra Fallén, 1810

See generic synonymy.

Diagnosis. The subgenus Ephydra is distinguished from other subcongeners by the following combination of characters:

Head: Cruciate, interfrontal setae 1 pair, well develo ped. Palpus normally developed.

Thorax: Coloration of mesonotum generally shiny, at least partially; both males and females with well-developed pair of prescutellar acrostichal setae. Crossvein dm-m merged with vein M₁ at nearly right angle; costal vein ratio 0.24-0.27; M₁ vein ratio 0.68-0.81. Length of tarsal claws variable, long in the glauca Group, as long as tarsomere 5, shorter in the riparia Group, about half length of tarsomere 5.

Abdomen: Male terminalia with surstyli relatively stout and distally blunt; gonite bearing two very characteris tically placed, subapical setae; aedeagus swollen at base or with strongly recurved basal process.

Third-instar larva (based on E. riparia; Yakovleva et al. 2024: 360-375): Generally white, somewhat transparent; body elongate, body length 9.80-12.15 mm, siphon length 1.90-2.80 mm; body with 12 segments; a membranous pseudocephalon capable of extending from and retracting within thorax, pseudocephalon with complex set of sensory and oral structures; 2-segmented antenna; maxillary sensory organ with two separate groups of sensilla; comb-like oral papilla located dorsally and dorsolaterally of mouth; three thoracic segments legless; eight abdominal segments bearing a pair of prolegs, caudal segment with a branched respiratory siphon dorsally and largest pair of prolegs ventrally; prolegs with distal cluster of long; claw-like spines of prolegs curved backward, except those on caudal prolegs curved forward; anus behind bases of prolegs.

Distribution. See generic treatment.

Remarks. This subgenus comprises all species of Ephydra except E. gracilis, the only species included in the subgenus Halephydra. All species occurring in the Western Hemisphere belong to either of two species groups: the glauca and riparia groups.

Subgenus Halephydra Wirth, 1971

HalephydraWirth 1971: 371 (feminine; type species: Ephydra cinerea Jones (= E. gracilis Packard), by original designation). - Mathis and Zatwarnicki 1995: 245-246 [world catalog].

Diagnosis. The subgenus Halephydra is distinguished from other subgenera of Ephydra by the following characters: General coloration dull, almost entire body grayish, only mesofrons shiny and dark; moderately small to mode rately large shore flies, body length 3.70-3.3 mm.

Head: Cruciate interfrontal setae weak or lacking. Palpus relatively small.

Thorax: Acrostichal setulae in two rows; 5 (1+4) dorsocentral setae, anterior seta in front of suture. Scutellum short and convex; crossvein dm-m merged with vein M₁ at acute angle; costal vein ratio 0.40; M₁ vein ratio 0.61. Forebasitarsus of male with elongate, irregular depression on lateral surface.

Abdomen: Structures of male terminalia as follows: epandrium moderately elongate with medial furrow and broad distal plate bearing surstyli; two clumps of long stout yellowish setae on each side near base of surstyli; surstyli long, digitiform, relatively close together, each bearing several long fine scattered setae on medial surface; aedeagus narrow, strongly sclerotized basally, expanded beyond slender distal arch of hypandrium forming a more or less cylindrical, large, funnel-like, palely sclerotized structure; gonites sickle-shaped, each bearing a well-developed proximal spine and smaller one near middle. Female terminalia: Female ventral receptacle with extended process relatively broad, length about twice width of operculum.

Third-instar larva: generally white, somewhat transpa rent; length ca. 10 mm, respiratory tube 5 mm to fork, each fork about 1.6 mm and with basal filament 2 mm; eight pairs of rather long prolegs; hind prolegs with a longer common base and shorter divided portion than anterior prolegs; res piratory tube bearing ventrally near base a pair of long filaments, distal filaments each bearing a small spiracle at apex.

Distribution. This species is widespread in Western North America as far east as Illinois and Ohio. It also occurs on the Hawaiian Islands (Kauai, Oahu) and on the Bahamas and Trinidad and some islands of the West Indies (Bonaire, Puerto Rico, and the Virgen Islands). This species is remarkably vagil, enabling this species’ exploitation of rather disparate habitats with the appropriate saline conditions.

Remarks. Wirth (1971: 371) noted that many structures of the male terminalia of this subgenus resemble those of Ephydrella Tonnoir and Malloch, a genus of 10 species that is only known from Australia and New Zealand. In our ana lysis and in all weighing schemes, the subgenus Halephydra was recovered as the sister group to the subgenus Ephydra.

Ephydrella Tonnoir & Malloch, 1926

Figs 31-33

EphydrellaTonnoir and Malloch 1926: 6 (feminine; as a subgenus of Ephydra; type species: Ephydra novaezealandiae Tonnoir and Malloch 1926, original designation). - Cresson 1935: 354 [generic status]. - Harrison 1959: 244-249 [fauna of New Zealand]. - Marshall and Wright 1974: 301-318 [ultrastructure of hindgut]. - Bock 1987: 155-166 [revision of Australian species]. - Mathis 1989: 647-648 [Australasian/Oceanian catalog]. - Mathis and Zatwarnicki 1995: 247-248 [world catalog].

MydaezealandiaSalmon 1937: 359 (type species: Mydaezealandia glauca Salmon 1937 (= Ephydrella spathulata Cresson 1935), original designation). - Salmon 1950: 2 [synonymy].

Diagnosis. Ephydrella is distinguished from other ge nera of the tribe Ephydrini by the following combination of characters: moderately large shore flies, body length 3.0-6.0 mm.

Figures 31-36
Ephydrella and Halmopota. Ephydrella novaezealandiae, (31) head anterior; (32) head lateral; (33) thorax dorsal. Halmopota salinarius, (34) head anterior; (35) head lateral; (36) thorax dorsal.

Head: Frons with shiny, metallic mesofrons, parafrons relatively dull, appearing somewhat “membranous”; two well-developed, lateroclinate fronto-orbital setae; cruciate interfrontal setae lacking; paravertical setae not evident; medial and lateral vertical setae well developed. Basal flagel lomere lacking a lateral seta; arista long, almost double length of basal flagellomere, basal half somewhat swollen; dorsal aristal branches not evident, at most arista appearing macropubescent. Face with larger setae at lateral and oral margins; 1 large genal seta.

Thorax: Mesonotum dark colored, brown to metallic dark green or blue, similar to frons, with longitudinal light gray stripes in area of acrostichal tracks, scutellum triangular, posterior angle rounded, relatively acutely angulate, or narrowly truncate. Chaetotaxy: 1 well-developed pair of prescutellar acrostichal setae, otherwise as setulae; 4 (1+3) or 5 (1+4) well-developed dorsocentral setae, sometimes these appreciably reduced, posterior seta displaced laterally; 1 postpronotal seta; 1 presutural supra-alar seta; 1 supra-alar seta; 1 postalar seta; 2 lateral scutellar setae; prosternal setulae sparse on at least posterior portion; anepisternum with 1 long seta; katepisternum with 1 long, dorsoclinate seta. Wing generally hyaline; R stem vein bare above; costal vein ratio 0.23-0.25; M₁ vein ratio 0.68-0.76. Male hindfemur not differing markedly from fore- or midfemur, lacking stout setae; male hindtibia lacking tuft of setulae; male hindtarsi cylindrical, normal; pulvilli much reduced or absent; tarsal claws long and nearly straight.

Abdomen: Male with five visible tergites, female with 6-7; coloration similar to that of notopleuron, often submetallic but with varying levels of microtomentum. Male terminalia symmetrical, epandrium longer than wide, bearing prominent surstyli, these often elongate, with medial, often small triangular structure between surstyli, with medial fissure; aedeagus in lateral view cylindrical, moderately slender, base with more sclerotized, distinctly curved process; phallapodeme in lateral view elongate, keel distinct, either apices rod-like, slender; gonite sheathing aedeagus, usually longer than wide, variously shaped, but usually acutely pointed apically; subepandrium narrow band than arches over base of aedeagus; hypandrium shallowly v-shaped, angle very obtuse. Female terminalia: Female ventral receptacle with small papilla-like operculum; egg guide sternites bearing two pairs of strong setae.

Natural history: Bock (1987) observed that larvae of some Australian species are associated with marine algae of the genus Cladophora.

Distribution. Ephydrella is thus far only found on Australia and New Zealand.

Remarks. Ten species have been described thus far, all from Australia and New Zealand, and at least one species from New Zealand has not been described.

The shape of the surstylus and its relative length compared to the length of the medioventral process are used extensively to identify species of Ephydrella.

Halmopota Haliday, 1856

Figs 34-36

HalmopotaHaliday in Walker 1856: 346 (masculine; type species: Ephydra salinariaBouché, 1834, monotypy). - Becker 1926: 96-98 [review of Palearctic species]. - Giordani Soika 1958: 207-216 [revision]. - Canzoneri and Meneghini 1974: 147-151 [revision]; 1983: 151-156 [review of Italian species]. - Papp 1975: 92-93 [review of Hungarian species]. - Cogan 1984: 171-172 [Palearctic catalog]. - Krivosheina 1989: 18-23 [revision]. - Mathis and Zatwarnicki 1995: 248-249 [world catalog].

Diagnosis. Moderately large shore flies, body length 4.0-5.5 mm, generally appearing dull, densely microtomentose, grayish.

Head: Frons dull, gray, brown or velvety black, uniform, some species with silvery white spots; 2 ocellar setae; 3 latero clinate fronto-orbital setae; lacking cruciate interfrontal setae; postvertical setulae weak; lateral and medial vertical setae present. Antenna black, pedicel sometimes brownish; arista glabrous, base broad, generally black to yellowish brown. Face projected anteriorly, arched, face and gena silvery white to dark gray; face with one strong seta and several setulae; gena with 3-5, dorsally curved setae; facial setae aligned with parafacial suture, setae lacking along ventral martin. Clypeus prominent, clearly projected ventrally beyond ventral oral margin; oral opening large, gaping.

Thorax: Mesonotum gray, brown, or velvety black, unicolorous or with stripes and spots. Five dorsocentral setae (2+3); two rows of acrostichal setae, prescutellar pair larger; 1 postpronotal seta; 1 presutural supra-alar seta; 2 supra-alar setae; lateral scutellar setae not arising from tubercles; shape of scutellum variable; katepisternum and anepisternum appearing pubescent, 1-4 katepisternal setae; 0-1 anepisternal seta. Wing mostly hyaline, with sharp separation of subcostal, proximity of middle cubital vein, disc shape at rear edge of wing; lacking a spur vein; halter faintly yellowish; costal vein ratio 0.21-0.23; M₁ vein ratio 0.72-0.74. Legs gray, apices of tibia and tarsi reddish brown; pulvilli present but rudimentary; tarsal claws relatively long and straight.

Abdomen: Gray to greenish, microtomentose, numerous short setulae. Male terminalia: Epandrium shield-like, ovate to ellipsoidal, with ventromedial fissure; cerci comparatively elongate, length about equal to paired ventral extensions of epandrium; gonite in lateral view nearly straight, apex variously shaped, apex arrow-like, pointed or excavated subapically; aedeagus in lateral view tubular, parallel sided to tapered, curved or almost L-shaped. Female terminalia: Female ventral receptacle with operculum tube-like, much smaller than extended process, trapezoidal; extended process broadly curved, widest medially, with neck that extends into operculum. egg guide sternites bearing two pairs of weak setae.

Third-instar larva: Prolegs along venter of abdominal segments.

Natural history: Adults and immature stages are associated with saline habitats, usually shorelines. Sometimes the salinity is very high.

Distribution. Thus far, species of Halmopota are found exclusively in the Palearctic Region and can be conveniently summarized by Turkey (H. anatolicus Canzoneri and Meneghini, H. tomentosus Canzoneri and Meneghini) and Tibet (H. chinensis Krivosheina, H. hutchinsoni Cresson, H. kozlovi Becker, H. villosa Becker) plus the following: H. mediterraneus Loew (Algeria, Egypt, Iraq, Iran, Morocco, Spain, Syria, Tibet, Turkey), H. insignis (Becker) (Russia, Ukraine), H. salinarius (Bouché) (Germany, Poland, Russia), H. septentrionalis Canzoneri and Meneghini (Bulgaria, Italy, Tadzhikistan, Turkey, Turkmenistan), and H. stackelbergi Krivosheina (Tadzhikistan).

Remarks. While having sympatric species distributions is not unusual in Ephydridae, this condition for at least some species of Halmopota may suggest the need to again revise the included species. To that end, we have provided more detailed distributional data for all described congeners (see above).

Although the generic name, Halmopota, ends with the letter a, it is a masculine noun, and the species’ epithets should agree in gender.

Neoephydra Mathis, 2008

Figs 37-51

Dimecoenia in part of authors [misidentification], not Cresson 1916: 152. - Wirth 1968: 23 [catalog of South American species, distribution]. - Lizarralde de Grosso 1989: 57-58 [fauna of Argentina]. - Mathis and Zatwarnicki 1995: 238-240 [world catalog].

NeoephydraMathis 2008: 9 (feminine; type species: Neoephydra araucaria Mathis 2008, original designation). - Mathis and Marinoni 2016: 31-74 [revision, Neotropical species].

Diagnosis. Neoephydra is distinguished from other ge nera of Ephydrini by the following characters: medium-sized to large shore flies, body length 3.00-5.30 mm.

Figures 37-51
Neoephydra. Neoephydra_araucaria, (37) habitus. Neoephydra mallonota, (38) head anterolateral; (39) thorax dorsal; (40) epandrium and cerci posterior; (41) internal structures of male terminalia lateral; (42) male terminalia lateral. Neoephydra neotropica, (43) head anterolateral; (44) thorax dorsal; (45) epandrium and cerci posterior; (46) male terminalia lateral; (47) internal structures of male terminalia lateral. Neoephydra trichina, (48) head lateral; (49) thorax dorsal; (50) epandrium and cerci posterior; (51) male terminalia lateral.

Head: Mesofrons with vestiture variable; lacking cruciate, interfrontal setae; lateroclinate, fronto-orbital setae either 2 or 5-6, not 3; basal flagellomere lacking large seta inserted on lateral surface; arista moderately short, thickened basally, with macropubescent vestiture dorsally, apical half style-like, bare; postocular setae variable; large facial setae declinate; gena moderately high to high, gena-to-eye ratio 0.30 or larger.

Thorax: Chaetotaxy: Acrostichal setae, including a prescutellar pair, not well-developed; dorsocentral setae 5 (1+4), development variable; supra-alar seta variable; presutural supra-alar seta lacking; intrapostalar seta present, although sometimes weak. Wing generally hyaline; costal vein ratio 0.19-0.36; M₁ vein ratio 0.64-0.86. Hindtibia lacking apical seta; tarsal claws nearly straight; pulvilli essentially absent.

Abdomen: Male terminalia symmetrical, epandrium longer than wide; surstyli fused medially except near apices and with 1-2 lateral projected processes or prongs in addition to apical prominences; aedeagus in lateral view shallowly crescent-shaped and generally quite slender, at least apically. Female terminalia: Female ventral receptacle with small papilla-like operculum.

Natural History: Like many taxa of the subfamily Ephy drinae, specimens of Neoephydra inhabit diverse and what would appear to be environments inimical to life. Oliveira (1954a) noted that Dr. Herman Lent found larvae, pupae, and adults of a Chilean species in the hot effluent of a high altitude, hot water geyser located at El Tatio (5200 m), near San Pedro de Atacama. Although the temperature of the water was not taken, Dr. Lent stated that it was sufficiently hot to cook an egg. Dr. Lent also observed a small, predatory toad, Telmatobius peruvianus Wiegmann (Anura: Leptodactylidae), whose diet consisted solely of freshly emerged, adult flies.

Numerous larvae and pupae of a second species, collected in southern Brazil, were found to inhabit warm, algae-covered, and often saline water that had accumulated in depressions of large rocks near the seashore (Oliveira 1954b, 1958). Water evaporation from these shallow depressions is rapid, accounting for the concentration of salts.

Hennig (1943) and Oliveira (1954b, 1958) described and illustrated the larvae of four species belonging to this genus. Based on these figures, larvae of Neoephydra are typical of the tribe, with eight pairs of claw-bearing prolegs on the ventral surface, the terminal pair being larger and with crochets opposable to those of the other prolegs. The posterior spiracles are borne on a long respiratory tube which bifurcates posteriorly.

Distribution. Members of Neoephydra are only known from the Neotropics and some island in the south Atlantic Ocean, where they are widespread and occur in habitats similar to those of the Holarctic genera Ephydra Fallén and Setacera Cresson.

Remarks. Neoephydra is the generic name for most South American species that had been placed in the genus “Dimecoenia.” As noted by Steyskal (1970) and Wirth (1971), the Neotropical species, which were treated as congeners of Dimecoenia (Wirth 1968), are structurally dissimilar from the Nearctic species. We came to the same conclusion as Steyskal and Wirth after studying structures of the male terminalia. To identify species, particular attention should be given to structures of the male terminalia and female ventral receptacle.

Three species groups are also recognized (the arauca ria, dasycephala, and neotropica groups). These groups were proposed for specimens that are dissimilar superficially from the typical Neoephydra (araucaria Group) but which have structures of the male and/or female terminalia that closely resemble those of other similar aggregates. Mathis and Marinoni (2016) chose the informal category of “species group” for these groups because of its flexibility, without encumbering additional, relatively fixed nomenclature, such as would be required for the subgeneric category.

The monophyly of Neoephydra is established by the following characters: (1) Conformation of the male terminalia: The surstyli are fused medially except near their apices and each surstylus bears one or two additional, anterolateral prongs. This conformation is unique within the subfamily Ephydrinae. (2) Conformation of female ventral receptacle: All species groups have a small, papilla-like operculum, which is also apparently unique to females of Neoephydra.

It is likely that the species groups of Neoephydra are monophyletic, although the araucaria Group lacks characterization by derived character states. The monophyly of the remaining groups is well established, as evidenced by the appropriate characterization heading each group’s treatment.

Key to species groups of Neoephydra

1. Lateroclinate, fronto-orbital setae 5-6; postocular setae well developed, prominent along ventral margin of eye .................... dasycephala Group [N. dasycephala Mathis and Marinoni, N. mallonota Mathis and Marinoni, N. shewelli Mathis and Marinoni]

1’. Lateroclinate, fronto-orbital setae 2; postocular setae variable but not prominent along ventral margin of eye .................... 2

2. Setation generally weak, fronto-orbital setae much shorter than width of frons; mesofrons mostly microtomentose; antennal groove deeply impressed; disc of scutellum gray, contrasted distinctly with brown scutum .................... neotropica Group [N. neotropica Mathis and Marinoni]

2’. Setation strongly developed, length of fronto-orbital setae nearly equal to width of frons; mesofrons shiny with metallic reflections; antennal groove not deeply impressed; disc of scutellum concolorous with posterior portion of scutum .................... araucaria Group [N. abrupta (Cresson), N. araucaria Mathis, N. caesia (Wulp), N. chilensis (Macquart), N. ciligena (Rondani), N. inca Mathis and Marinoni, N. lenti (Oliveira), N. penai Mathis and Marinoni, N. pravoneura (Hendel), N. prionoptera (Thomson), N. trichina Mathis and Marinoni, N. zurcheri (Hendel)]

Notiocoenia Mathis, 1980

Figs 52-66

NotiocoeniaMathis 1980: 12 (feminine; type species: Notiocoenia paniculata Mathis 1980, original designation). - Lizarralde de Grosso 1989: 59 [fauna of Argentina]. - Mathis and Zatwarnicki 1995: 249-250 [world catalog]. - Mathis and Marinoni 2016: 14-23 [revision of Neotropical species].

Diagnosis. Specimens of Notiocoenia are similar to those of Coenia but are distinguished from the latter and other genera of Ephydrini by the following combination of characters: Small to moderately large shore flies, body length 1.90-4.20 mm; mostly grayish brown to brown, generally appearing dull but subshiny to shiny over much of dorsum.

Figures 52-66
Notiocoenia. Notiocoenia paniculata, (52) head anterior; (53) head lateral; (54) thorax dorsal; (55) abdomen dorsal; (56) epandrium and cerci posterior; (57) male terminalia lateral; (58) internal male terminalia lateral; (59) female ventral receptacle anterior; (60) female ventral receptacle lateral. Notiocoenia pollinosa, (61) head anterior; (62) head lateral; (63) thorax dorsal; (64) epandrium and cerci posterior; (65) internal structures of male terminalia lateral; (66) internal structures of male terminalia.

Head: Wider than high from anterior view; frons mostly flat, wider than long, vestiture more or less uniform, dull, microtomentose, mostly unicolorous brown, margins of mesofrons indicated by shallowly impressed furrow, otherwise undifferentiated from parafrons, lacking large setae, cruciate or otherwise; well-developed, lateroclinate, fronto-orbital setae 2, plus 1 much smaller proclinate seta anterior of larger setae; paravertical seta small, inconspicuous, none 1/2 length of vertical seta; well-developed, ocellar setae 1, slightly divergent; small postocellar setae 2-3 setulae; medial vertical setae well developed, lateral vertical seta either well developed or lacking. Antenna normally developed, dark colored, basal flagellomere considerably longer than high, rounded apically; pedicel bearing several setae, especially on medial and ventral surfaces, bearing one large, dorsally erect seta on dorsum; arista longer than combined length of other antennal segments, macropubescent or bearing short hairs dorsally. Face protuberant, broadly transversely arched, setulose to setose; interfoveal hump evident but variously developed; vestiture densely microtomentose. Eye subspherical, slightly higher than wide. Gena short, gena-to-eye ratio 0.20 or less; well-developed, genal seta 1. Mouthparts generally retracted into oral opening, clypeus not exposed; maxillary palpus dark; prementum longer than wide; microtomentose to microtomentose, setose.

Thorax: Vestiture variable, dull to shiny, generally becoming shinier posteriorly; coloration grayish brown to blackish brown. Pleural areas generally becoming paler colored ventrally; humeral callus, part of anepisternum, and katepisternum grayish tan to whitish tan, otherwise pleural areas darker brown; forecoxa gray to silvery gray, contrasting with remainder of pleural areas. Chaetotaxy as follows: Acrostichal setae when present arranged in two rows, larger setae mostly anterior of transverse suture; lacking well-developed, prescutellar seta; well-developed, dorsocentral setae 4 (1+3), rarely 5 (2+3), anterior 1-2 setae smaller, several smaller setae anterior of larger setae; interalar setae 2, anterior seta inserted just posterior of transverse suture, posterior seta posterior of level of posteriormost dorsocentral seta; postpronotum either bare or bearing 2-3 setulae, none more than 1/4 length of posterior, notopleural seta; presutural interalar seta 1; interalar setae 2, rarely 3, anterior seta inserted just posterior of transverse suture, posterior seta smaller, inserted just posterior of posteriormost dorso central seta; postsutural, supra-alar seta variable; postalar seta well developed; disc of scutellum mostly bare, bearing 2-3 setulae, or bare; lateral scutellar setae 2; notopleural setae 2, inserted near each ventral angle; anepisternal seta 1, inserted near middle of posterior edge, numerous smaller setae, particularly toward dorsal and posterior margins; prosternum bare; katepisternal seta 1, with 1-2 smaller setae around larger seta; midcoxa with 1 larger seta. Wing hyaline to palely infuscate; R stem vein bare dorsally; halter yellowish to pale brown; costal vein ratio 0.13-0.16; M₁ vein ratio 0.55-0.68. Legs variable, femora swollen to slender; coloration rufous to black; pulvilli well developed; tarsal claws short and distinctly curved; pulvilli well developed; tarsal claws short and distinctly curved; hindfemur of male not differing markedly from fore- or midfemur, lacking stout setae as above; hindtibia of male lacking tuft of setulae; hindtarsi of male cylindrical, normal.

Abdomen: Dorsum either darker brown, with some bluish coloration or blackish, subshiny to shiny; tergite 5 of variable length compared to tergite 4. Male terminalia: Surstylus either fused indistinguishably with ventral margin of epandrium (paniculata Group) or fused but distinct and setose (pollinosa Group); aedeagus either a long, slender, tapered process, apex slightly coniform or produced ventrally as two symmetrical narrow processes. Female terminalia: Female ventral receptacle with tiny, flat operculum and a very large, roughly C-shaped extended process in lateral view; females sternites square to rectangular, relatively wide (Costa et al. 2024).

Distribution. The composite distribution for species of this genus is Neotropical and extends from 24°-53°S along the east and west slopes of the Andes Mountains.

Remarks. Although the monophyly of Notiocoenia appears to be well established, its relationship to other taxa within Ephydrini is not as evident. Although we suggest a sister group relationship with Coenia, as indicated in the cladogram, the evidence to support this alliance is not wholly convincing.

See also remarks under Austrocoenia.

Following the precedent of Mathis and Marinoni (2016), we recognize two species groups, which are identified in the following key.

Key to species groups of Notiocoenia

1. Lateral vertical seta present, length subequal to medial vertical seta; postsutural, supra-alar seta either lacking or much reduced; arista at most macropubescent; postpronotum bearing 2-3 setulae; wing appearing dull, palely infuscate, 2 white spots on either side of crossvein dm-m .................... pollinosa Group [N. pollinosa Mathis]

1’. Lateral vertical seta lacking; postsutural, supra-alar seta present, length subequal to postalar seta; arista micropectinate, hair length about 1/2 height of basal flagellomere; postpronotum bare; wing appearing shiny, mostly hyaline, lacking white spots as above .................... paniculata Group [N. paniclulata Mathis, N. acutella Mathis]

Paracoenia Cresson, 1935

Figs 67-74

ParacoeniaCresson 1935: 356 (feminine; type species: Coenia bisetosaCoquillett 1902, original designation). - Wirth 1965: 755-756 [Nearctic catalog]. - Mathis 1975: 65-85 [revision of Nearctic species]. - Zack 1983a: 487-497 [biology and immature stages of P. bisetosa]. - Mathis and Zatwarnicki 1995: 250-252 [world catalog]. - Yakovleva et al. 2024: 360-375 [biology and immature stages of P. fumosa].

Diagnosis. Paracoenia is distinguished from other genera of the tribe Ephydrini by the following combination of cha racters: Small to large shore flies, body length 2.10-4.40 mm; dark colored and often with subshiny, metallic reflections.

Figures 67-86
Paracoenia, Paraephydra and Setacera. Paracoenia wirthi, (67) head anterior; (68) head lateral; (69) thorax dorsal; (70) epandrium and surstyli posterior; (71) epandrium and surstyli lateral; (72) male 5th tergite lateral; (73) male 5th sternite ventral; (74) female ventral receptacle lateral. Paraephydra freitasi, (75) head anterolateral; (76) thorax dorsal; (77) epandrium and cerci posterior; (78) internal structures of male terminalia lateral; (79) surstylus lateral; (80) gonite lateral; (81) female ventral receptacle lateral. Setacera trichoscelis, (82) head anterolateral; (83) thorax dorsal; (84) internal structures of male terminalia lateral; (85) male terminalia lateral; (86) fused surstyli posterior.

Head: Face projected, transversely arched; paravertical setae large, subequal to vertical setae. Two well-developed lateroclinate fronto-orbital setae.

Thorax: Postpronotal seta distinct, length at least 1/2 as long as posterior notopleural seta; dorsocentral setae 5 (1+4); scutellum with dorsum convex; prosternum bare. R stem vein bearing 1-2 setulae above, inserted beyond transverse septum; costal vein ratio 0.19-0.27; M₁ vein ratio 0.81-0.92. Hindcoxa with row of setae posteriorly along ventral margin; tarsal claws short and distinctly curved, comparatively short; pulvilli well developed.

Abdomen: Male terminalia: Surstyli distinct as elongate, narrow, arm-like projections, projections oriented ventrally; a medial, triangular process between surstylar arms; gonite (sometimes called hypandrial process) well developed, sheathing aedeagus.

Third-Instar larva: Body length 9.50-18.80 mm; body fusiform, integument translucid; 12 segmented; 3-segmented antenna; maxillary (terminal) sensory organs (consisting of seven sensillae, separated by flattened ridges in 2 groups, 2 + 5); 3 legless thoracic segments, 1^st thoracic segment with two anterior spiracles; eight legless abdominal segments; caudal segment with anus ventrally, elongated as a long retractile, branched respiratory tube, tube length 30-50% body length.

Natural history: A few species of this genus occur in the effluent of hot springs, and some are uniquely found only at these sites. Moreover, some of the springs are sulfurous and otherwise inimical to most other forms of life. These species are as follows: P. calida Mathis from Wilbur Hot Springs (39°2.3’N, 122°25.3’W) in Colusa County, California; P. quatei (Wirth) from Sulphur Mountain Spring (34°25.7’N, 119°05.6’W) in Ventura County, California; P. beckeri (Kuntze) from Acque Albule (41°54.2’N, 12°29.8’E), a sulfurous spring near Tivoli, Roma, Italy. Adults and immature stages of these three species were collected only at these respective and specific sites despite efforts to sample them from nearby habitats and elsewhere (Wirth 1954 for P. quatei; Giordani Soika 1956a for P. beckeri; and Mathis 1975 for P. calida). Wirth (1954) described the 3^rd-instar larva of P. quatei, which has small pseudopods along the ventral surface of segments, and these lack the long crochet-like setae, found more typi cally in larvae of Ephydra (Aldrich 1912).

A fourth possible species that may occur in hot springs is P. ampla Mathis, which is only known from Los Angeles, Los Angeles County, California. M.C. VanDuzee collected the holotype male in April of 1915. We wonder if the specific site were a hot spring, such as Alvarado Hot Springs, and if more specimens could be found there or at another hot springs in the area.

These species were perhaps preadapted to live in association with hot springs, as other congeners, such as P. wirthi Mathis (Tecopa Hot Springs) and P. turbida (Curran) (Yellowstone hot springs) have been collected in and on the effluent of some hot springs in addition to occurring in cold-water wetlands. The “preadaption” may involve the algal food source that lives in these hot springs and other aquatic sources.

Remarks. The lineage comprising Paracoenia and related genera in our data and analysis the sister group to the remaining taxa of Ephydrini. This lineage plus the remaining taxa of Ephydrini, as here delimited, is characterized by the following character states (some have become modified secondarily): 1. Number of dorsocentral setae: Although other genera of the subfamily Ephydrinae sometimes have five pairs of dorsocentral setae (e.g. Notiocoenia Mathis and Austrocoenia Wirth), the anterior pair (or pairs) is weakly developed. There are five well-developed pairs only in members of Ephydrini (the anterior pair is presutural; specimens of Cirrula gigantea have the anterior four pairs of dorsocentral setae are weakly developed, a condition we interpret to be secondary). 2. Development of intrapostalar seta: In most species of the family, the intrapostalar seta is either lacking or is very much reduced, less than one-half the length of the postalar seta. In members of this lineage, the intrapostalar seta is frequently as long. 3. Setal vestiture of proepisternum: Throughout most of the family the proepisternum is bare of setae (although frequently it is thinly to densely microtomentose). In members of this lineage, there are numerous setulae that are generally conspicuously evident.

Key to subgenera of Paracoenia

1. Both supra-alar and katepisternal setae either lacking or much reduced; midfemur of male lacking row of closely set setae along posteroventral surface; apical 4 tarsomeres explanate and comparatively short; pulvilli lacking; basal flagellomere short, less than length of pedicel; general coloration black .................... Subgenus Thiomyia Wirth [P. (Thiomyia) quatei (Wirth)]

1’. Both supra-alar and katepisternal setae well develo ped; midfemur of male with row of closely set setae along posteroventral surface; apical 4 tarsomeres normally developed, cylindrical; pulvilli evident; basal flagellomere short, less than length of pedicel; gene ral coloration olivaceous gray to dark green or bluish green .................... Subgenus Paracoenia Cresson [P. (Paracoenia) ampla Mathis, P. (P.) beckeri (Kuntze), P. (P.) bisetosa (Coquillett), P. (P.) calida Mathis, P. (P.) fumosa (Stenhammar), P. (P.) fumosalis Cresson, P. (P.) turbida (Curran), P. (P.) wirthi Mathis]

Subgenus Paracoenia Cresson, 1935

ParacoeniaCresson 1935: 356 (as a genus; feminine; type species: Coenia bisetosaCoquillett 1902, original designation). - Mathis and Zatwarnicki 1995: 250-251 [world catalog].

Diagnosis. This subgenus is similar to the subgenus Thiomyia but is distinguished by the following combination of characters: Generally olivaceous gray to dark greenish or bluish brown; setation generally well developed.

Head: Frons short. Antenna slender, basal flagellomere longer than wide; arista with dorsal rays about equal in length to length of basal flagellomere. Face high, height more than twice length of largest setae along oral margin; face generally conspicuously setose; antennal grooves evident but not as concave as Thiomyia.

Thorax: Dorsocentral setae 5; postsutural supra-alar seta well developed, subequal to length of anterolateral, postalar seta; katepisternal seta well developed. Wing gene rally hyaline to faintly infuscate; halter whitish yellow to yellow; costal vein ratio 0.19-0.27; M₁ vein ratio 0.81-0.92. Femora more swollen than in Thiomyia, nearly twice width of tibiae; midfemur of male with comb-like row of closely set setae along posteroventral margin; tarsomeres normally developed, cylindrical, not explanate, tarsal claws curved, short; pulvilli evident, well developed.

Abdomen: Tergites wide, particularly tergite 2 and tergite 3, each 3X wider than long; tergite 5 of male generally with a ventrolateral process oriented along plane of body. Female terminalia: Female ventral receptacle with large operculum, helmet-like, wider than high, extended process comparatively short, about equal to height of operculum.

Distribution. The composite distribution of this subgenus is Holarctic, with six species occurring across much of the Nearctic Region and two species occurring primarily in the western Palearctic Region (Great Britain to Iran, Sweden to Morocco). Two species, P. calida Mathis (Wilbur Hot Springs [430 m; 39°02.2’N, 122°25.1’W], Colusa County, California) and P. beckeri (Kuntze) (Rome, Italy) have very restricted distributions and are essentially known only from their respective type localities, which are springs. These isolated habitats are perhaps candidates for legislative protection.

Remarks. Except for P. ampla, P. calida and P. beckeri, these species have relatively wide distributions, and they often occur sympatrically.

Subgenus Thiomyia Wirth, 1954

ThiomyiaWirth 1954: 196 (as a genus; feminine; type species: Thiomyia quatei Wirth 1954, original designation). - Mathis 1980: 11 [revised status]. - Mathis and Zatwarnicki 1995: 251-252 [world catalog].

Diagnosis. This subgenus is similar to the subgenus Paracoenia but is distinguished by the following combination of characters: General body coloration dark blackish brown to black; setation generally weakly developed, particularly on abdomen.

Head: Frons elongate, extended anteriorly nearly to level of face; antenna short, basal flagellomere as wide as long; length of dorsal rays of arista short, approximately equal to one-half width of basal flagellomere. Face short, subequal to length of longer facial setae along oral margin; face with much longer setae along margin, remainder of face at most setulose; antennal fovea well developed, deeply impressed.

Thorax: 4-5 pairs of dorsocentral bristles (2\2; 2\3); supra-alar seta lacking or much reduced, hairlike; katepisternal seta lacking. Wing generally infuscate, brownish; halter brownish; apex bluntly rounded; costal vein ratio 0.27; M₁ vein ratio 1.0; last section of vein M₁ shallowly but conspicuously arched. Femora slender, subequal to tibiae; middle femur of male lacking comb-like row of setae along posteroventral surface; apical 4 tarsomeres explanate and short; tarsal claws curved, short; pulvilli lacking.

Abdomen: Tergites narrower, width of tergites 2 and 3 at most twice length; male tergite 5 with ventral margin lacking any prong-like process. Female terminalia: Female ventral receptacle with large operculum, helmet-like, wider than high, extended process comparatively short, about equal to height of operculum.

Distribution. United States (California). This species is only known from Sulphur Mountain Spring (305 m; 34°25.7’N, 119°05.6’W) in Ventura County, California.

Remarks. Mathis (1980) relegated Thiomyia to subgeneric status because it was classified as the sister group of Paracoenia s. str. Wirth’s (1954) description of Thiomyia also included figures and descriptions of the third-instar larva and puparium. Wirth also provided observations on the natural history of the only included species, P. quatei (Wirth).

See remarks under the generic heading for specifics concerning the natural history of P quatei.

Paraephydra Mathis, 2008

Figs 75-81

ParaephydraMathis 2008: 4 (feminine; type species: Ephydrella frei tasiOliveira 1954c, original designation).

Diagnosis. Paraephydra is distinguished from other genera of Ephydrini by the following combination of cha racters: Moderately small to medium-sized shore flies, body length 2.40-3.80 mm; setation normally developed, not generally appearing pilose.

Head: Mesofrons shiny, with metallic luster, differentiated from microtomentose parafrons; cruciate interfrontal setae l; two well-developed lateroclinate setae antennal groove distinct but not deeply impressed; basal flagellomere lacking large seta inserted on lateral surface; arista as long or slightly longer than combined length of first 3 antennal segments, gradually tapered from base to apex, with subpectinate, dorsally branching rays on basal 2/3; postocular setae normally developed, not conspicuous; larger facial setae extended from interfoveal hump with 1-2, distinctly porrect to anaclinate.

Thorax: Females with one prescutellar, acrostichal setae; well-developed dorsocentral setae 4 (1+3); supra-alar seta present; presutural supra-alar seta lacking; intrapostalar seta either weakly developed or lacking; disc of scutellum concolorous with posterior portion of scutum; females lacking dense patch of setae between posterior 2 dorsocentral setae. Costal vein ratio 0.23-0.43; M₁ vein ratio 0.72-0.79. Hindtibia with apical, anteroventral seta, length equal to or larger than width of tibia at widest point.

Abdomen: Male terminalia: symmetrical; epandrium longer than wide, narrowed ventrally, fused almost imperceptibly with base of united surstyli; surstyli fused medially except at near apex; posterior surstylar process only slightly longer than lateral process; both processes apical; gonite, hypandrium, and apparently aedeagus fused to form one compact structure, curved anteriorly, wide basally, tapered to rounded apex. Female terminalia: Female ventral receptacle with operculum flat, disc-like.

Natural History: Like other ephydrines, Paraephydra occurs in wetlands. In southern Chile (Osorno Province), we collected specimens of P. stauros in a sedge meadow near the margins of small but apparently permanent ponds. Nothing is known about the immature stages or the microhabitat of the genus.

Distribution. Neotropical; widespread but uncommon, from Puerto Rico south through Brazil to Chile. None of the congeners is known to be sympatric.

Remarks. Paraephydra was proposed to accommodate two closely related species, P. freitasi (Oliveira) and P. stauros Mathis.

Sexual dimorphism is evident in the chaetotaxy of Paraephydra. Females, unlike males, have a prescutellar acrostichal seta that is larger than other acrostichal setulae. Based on this character, Oliveira (1954c) described P. freitasi in the genus Ephydrella, as that genus, unlike species of Neoephydra, lacks these setae.

Setacera Cresson, 1930

Figs 82-86

SetaceraCresson 1930: 116 (feminine; type species: Ephydra pacifica Cresson, by original designation). - Sturtevant and Wheeler 1954: 201-204 [key to North American species]. - Wirth 1965: 754-755 [catalog of North American species]; 1968: 24 [catalog of South American species]. - Mathis 1982b: 1-57 [revision, global]. - Zack 1983b: 10-25 [biology and immature stages S. needhami]. - Mathis and Zatwarnicki 1995: 252-254 [world catalog]. - Krivosheina and Ozerov 2020: 1190-1200 [review of Russian species].

Diagnosis. Setacera is distinguished from other genera of Ephydrini by the following characters: Moderately small to large shore flies, body length 2.46-5.85 mm.

Head: Mesofrons shiny, with metallic luster; cruciate, interfrontal setae lacking or weakly developed; lateroclinate, fronto-orbital setae 2 pairs; fronto-orbits shiny with metallic luster concolorous with mesofrons; basal flagellomere with prominent seta on lateral surface below aristal insertion; arista with subpectinate branching along dorsal surface from between onehalf to 2/3 of aristal length; dorsum of interfoveal facial ridge sloping very gradually; ridge projecting markedly forward in many species attaining broad apex from which arched face extends ventrally at nearly a right angle, face receding to oral margin in other species; antennal groove distinct but not deeply impressed; postocular setae normally developed, not conspicuous; larger facial setae declinate.

Thorax: Dorsocentral setae 5 (1+4); presutural supra-alar seta 1, generally subequal to posterior notopleural setae in species from Western Hemisphere. Costal vein ratio 0.28-0.30; M₁ vein ratio 0.84-0.90. Tarsal claws shallowly curved, nearly straight, comparatively long; pulvilli lacking or greatly reduced.

Abdomen: Structures of male terminalia symmetrical but unusually complicated by addition of several secondary processes and prongs; epandrium elongate; well-developed surstyli generally fused medially, projecting from ventral margin of epandrium. Female terminalia: Female ventral receptacle with operculum as high as wide, broadly rounded dorsally; extended process more or less J-shaped.

Natural History: The immature stages of Setacera and Ephydra closely resemble each other, and Johannsen (1935) considered them to be the most highly specialized of the family. Like larvae of Ephydra, those of Setacera are characterized by long, terminal respiratory tubes and by eight pairs of short, conical, abdominal prolegs, of which the last pair is the largest, with claws opposable to those of the other prolegs. Johannsen (1935) published a figure of the cephalopharyngeal skeleton of S. needhami, a species described inadvertently from the immature stages (Cresson 1935), and Foote (1982) described and illustrated the immature stages of S. atrovirens.

Unlike Ephydra, specimens of Setacera occur primarily in freshwater habitats, although Johannsen (1935) reared a specimen of S. atrovirens from a puparium collected in a brine pool near Ithaca, New York. Where members of Setacera do occur, even within what appears to be their preferred habitat, specimens are not collected frequently, and collection of a good series usually requires diligent persistence.

Most species seem to prefer lentic aquatic systems, especially where a layer of floating algae has accumulated on the water’s surface. This is the typical habitat of most species of Ephydrini, and their crochetbearing prolegs are apparently an adaptation to this habitat, allowing movement through and attachment to the algae.

Distribution. Among the genera of Ephydrini, Setacera is by far the most widely occurring, genus with species being found in all major faunal realms. The Neotropics, however, have a depauperate fauna.

Remarks. Some members of Setacera exhibit sexually dimorphic features that are probably secondary. Males of these species bear prominent hair-tufts of varying lengths at tibial apices and often on the coxae. The extent and length of tufts, or their absence, are excellent species-level characters.

Some species now included in Setacera were previously placed in the genus Ephydra Fallén, and some recent authors still prefer the precedent of Setacera as an included subgenus of Ephydra (Giordani Soika 1956b, Dahl 1959). Setacera is indeed closely related to Ephydra, as evidenced by the similarity of adults and immatures of both genera. Setacera, however, can be consistently distinguished in both sexes from all other genera of Ephydrini and its monophyly corroborated by the following synapomorphies: (1) Basal flagellomere seta: Aside from the arista, there are usually no other large structures emanating from the basal flagellomere. Specimens of Setacera, however, have a large seta inserted just below the aristal insertion on the lateral surface. (2) Vertico-orbits: Within the tribe Ephydrini, the vertico-orbits are generally either shiny or densely microtomentose and grayish, appearing dull. This area, in specimens of Setacera, is uniquely invested with a dense patch of microtomentum that appears velvety. Velvety areas occur elsewhere in a few species of the tribe (parafrons in Cirrula gigantea Cresson; frons and orbits in Ephydra auripes Aldrich) but not in the specific area as described for Setacera. (3) Genal seta: This seta is usually very prominent, arising below the eye. Although this seta is still larger than surrounding ones in specimens of Setacera, its comparative size is smaller, and for convenience, we have compared it with the length of the arista. (4) Cruciate interfrontal setae: Although some species of the tribe Ephydrini do not have these setae, most genera have at least a few species in which they occur. Consequently, our interpretation of the general groundplan of the tribe is for their presence, and their absence in Setacera is apparently unique, i.e. a synapomorphy. (5) Prescutellar acrostichal setae: As with the preceding characters, these setae are generally present in Ephydrini. We know of no specimens of Setacera, however, where they are present, and we interpret this apparent loss to be synapomorphic.

Mathis (1982b) recognized five monophyletic species groups that are relatively finely divided (for example, the aurata and trina groups could be combined) and are characterized as follows.

The aldrichi Group is the sister group of the pacifica group, and it is characterized and its monophyly established by: (1) Configuration of aedeagus: As before, the aedeagus is typically broadly rounded apically and almost as wide as long. Males of the aldrichi Group have a somewhat pointed aedeagus that we interpret to be apomorphic. (2) Configu ration of epandrium: Males of the aldrichi Group have an anteroventral, digitiform process, apparently a unique condition, and one that we interpret to be apomorphic.

The aurata Group (S. aurata (Stenhammar)) is the sister group of the trina Group, as evidenced by the distance between the cerci and setae on sternite 9. This distance is generally not greater than the height of the cerci. In females of this species group, the setae on sternite 9 re inserted farther ventrad, making the distance between them and the cerci conspicuously loner than the cercal height. Length of female sternite 8. The length is three to four times its width, not the more generalized five or more times. Length of female tergite 8. Tergite 8 in females is very long and partially accounts for the ventral position of sternite 9. This longer dimension of tergite 8 is a synapomorphy for this lineage. The aurata Group is distinguished from the trina Group by the shape of the epandrium. Although it is not uncommon for the epandrium to have appendages of various shapes, this is the only lineage to have a bluntly rounded, parallel-sided, posterolateral process arising from each side.

The breviventris Group (S. breviventris (Loew), S. multicolor (Soika), S. viridis Miyagi) occurs in the Old World and is characterized and its monophyly established by the following synapomorphy: Development of the presutural supra-alar seta weak. In most Ephydrini, this seta is well developed, usually as long as the presutural seta. In species of this group, however, this seta is weak and is considerably smaller than the presutural seta.

The micans Group (S. atrovirens (Loew), S. micans (Haliday)). This species group has a Holarctic distribution. The group is characterized and it monophyly established by the following synapomorphies: (1) Configuration of aedeagus. The aedeagus among most ephydrines is nearly as wide as long, and its apex is broadly rounded. In males of the micans Group the aedeagus is three to four times longer than wide, and its apex is acutely pointed. (2) Shape of female ventral receptacle. Usually, the operculum is nearly as high as the extended process, sometimes more so, and its width is subequal to its height. In females of the micans Group, the operculum is relatively small, both its width and height, especially compared to the size of the extended process.

The monophyly of the pacifica Group (S. durani Cresson, S. jamesi Mathis, S. needhami Johannsen, S. pacifica (Cresson), S. pilicornis (Coquillett), S. trichoselis Mathis) is established by: (1) Configuration of vertico-orbits: In Setacera this band is more or less broad and usually has a subanterior swelling. But in members of the pacifica Group this band is very narrow and is sometimes difficult to detect. The narrowed aspect of this character is interpreted to be a synapomorphy. (2) Configuration of female ventral receptacle: For most ephydrines, the operculum is typically wider than high. For females of the pacifica Group, however, the height is subequal to its width, an apomorphic character.

The trina Group (S. freidbergi Mathis, S. meneghinii Canzoneri, S. trina Collin). See our comments under the aurata Group for character evidence that these two group a closely related. The monophyly of the trina Group is established by the shape of the male gonite, which is unique for this group. A second character is the shape of the epandrium, which is similar in the species of this group, having the ventrolateral angles explanate and slightly recurved.

Key to species groups of Setacera

1.Arista with dorsally branching rays at most slightly longer than aristal width at base .................... 2

2. Antennal grooves microtomentose, whitish gray, contrasted with dorsum of interfoveal carina; vertico-orbits appearing velvety, contrasted with shiny fronto-orbits; presutural supra-alar seta well developed .................... micans Group

[S. atrovirens (Loew), S. micans (Haliday)]

2’. Antennal grooves concolorous with dorsum of interfoveal canina, shiny; vertico-orbits mostly shiny, concolorous with fronto-orbits; presutural supra-alar seta weakly developed .................... 3

3. Male tergite 5 shorter than tergite 3 or 4; male ster nite 3 and 4 without dense patch of stout setae toward posterior margin .................... breviventris Group [S. breviventris (Loew), S. multicolor (Soika), S. viridis Miyagi]

3’. Male tergite 5 as long as or longer than tergite 4; male sternite 3 and 4 with sense patch of stout setae toward posterior margin .................... 4

4. Surstylus in profile with slender, parallel-sided, apically truncate, lateral process that projects anteroventrally; gonite broad throughout most of length, lacking secondary process (northern Europe) .................... aurata Group [S. aurata (Stenhammar)]

4’. Surstylus in profile with posteriorly curved, ventrolateral process that is subapically enlarged; gonite conspicuously narrowed apically and with secondary process .................... trina Group [S. freidbergi Mathis, S. meneghinii Canzoneri, S. trina Collin]

5. Facial prominence in profile with dorsal slope longer than height of lower position of face; male tergite 5 broadly truncate, width of posterior margin more than half basal width .................... aldrichi Group [S. aldrichi Cresson]

5’. Facial prominence in profile with dorsal slope short, less than height of ventral portion of face; male tergite 5 broadly rounded or truncate, if truncate, width of posterior margin not over half basal width .................... pacifica Group [S. durani Cresson, S. jamesi Mathis, S. needhami Johannsen, S. pacifica (Cresson), S. pilicornis (Coquillett), S. trichoselis Mathis]

ACKNOWLEDGMENTS

We gratefully acknowledge the assistance and cooperation of many organizations and individuals who contributed to the field work and production of this paper. For reviewing a draft of this paper, we are grateful to Rosaly Ale-Rocha and Alessandra Rung. For general assistance, we thank Erin Kolski (USNM). We express appreciation to the curators and collections managers who loaned collections or facilitated work in their museums: David A. Grimaldi (AMNH); Jon K. Gelhaus and Jason D. Weintraub (ANSP); Ashley-Kirk Spriggs (BMNH); Laszlo Papp (HNHM); Trevor K. Crosby (NZAC). This study was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq process 234167/2014-9 and PQ grant process 311744/2021-4) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, including recent field work in Brazil (December 2009-June 2010) that resulted in most of specimens from Brazil that were studied in this paper (CNPq Visiting Researcher process 401609/2009-0), which we gratefully acknowledge. We thank Dianne Mathis for helping with all aspects of the production of this paper, especially the field work in Brazil. We also thank A. Bernardo Carvalho and his lab (Elisa Carvalho, Monica Carvalho, Susana Vaz) for hosting us while conducting field work along the coast of São Paulo, and José Albertino Rafael and Rosaly Ale-Rocha (INPA) for hosting us while working at INPA and conducting field work in the general environs of Manaus.

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ADDITIONAL NOTES

• ZooBank register
  https://zoobank.org/BA41F1A2-3C7A-4761-BC01-47232F498796
• How to cite this article
  Mathis WN, Marinoni L, Sepúlveda TA (2025) Phylogeny and taxonomy of the shore-fly tribe Ephydrini with comments on related tribes in Ephydrinae (Diptera: Ephydridae). Zoologia 42: e24044. https://doi.org/10.1590/S1984-4689.v42.e24044
• Published by
  Sociedade Brasileira de Zoologia at Scientific Electronic Library Online - https://www.scielo.br/zool

• Conselho Nacional de Desenvolvimento Científico e Tecnológico 234167/2014-9 and 311744/2021-4 and 401609/2009-0

Supplementary material 1

Table S1. Matrix of characters with complete list of terminal taxa included in the cladistic analyses.

Authors: W.N. Mathis, L. Marinoni, T.A. Sepúlveda

Data type: Species data.

Copyright notice: This dataset is made available under the Open Database License (ODbL - http://opendatacommons.org/licenses/odbl/1.0/). The ODbL is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Link: https://doi.org/10.1590/S1984-4689.v42.e24044

Appendix 1

Appendix 1. List of taxa included in the matrix (outgroups and taxa of the tribe Ephydrini)

Ingroups

1. (1) Austrocoenia aczeli Wirth

2. (2) Calocoenia (Calocoenia) platypelta (Cresson)

3. (2) Calocoenia (Leptocoenia) paurosoma Sturtevant and Wheeler

4. (3) Cirrula gigantea Cresson

5. (4) Coenia palustris (Fallén)*

6. (5) Dimecoenia spinosa (Loew)

7. (6) Ephydra (Ephydra) riparia Fallén

8. (6) Ephydra (Halephydra) gracilis Packard

9. (7) Ephydrella novaezealandiae Tonnoir and Malloch*

10. (8) Halmopota salinaria (Bouché)*

11. (9) Neoephydra araucaria Mathis

12.(9) Neoephydra dasycephala Mathis and Marinoni

13. (9) Neoephydra neotropica Mathis and Marinoni

14. (10) Notiocoenia paniculata Mathis

15. (10) Notiocoenia pollinosa Mathis

16. (11) Paracoenia (Paracoenia) bisetosa Coquillett

17. (11) Paracoenia (Thiomyia) quatei Wirth

18. (12) Paraephydra freitasi (Oliveira)

19. (13) Setacera pacifica Cresson

Outgroups

1. Amalopteryx maritima Eaton

2. Brachydeutera neotropica Wirth

3. Dagus rostratus (Cresson)

4. Haloscatella arichaeta Mathis

5. Hyadina furva Cresson

6. Ilythea spilota (Custis)

7. Parydra aquila (Fallén)

8. Philygria debilis Loew

9. Physemops nemorosus (Cresson)

10. Scatella stagnalis (Fallén)

11. Scatophila caviceps (Fallén)

Appendix 2

Appendix 2. List of characters and character states.

Head

1. Aristal length:

(0) longer than basal flagellomere;

(1) shorter than basal flagellomere.

2. Length of dorsal aristal rays:

(0) long rays, pectinate arista;

(1) short rays, pubescent arista.

03. Length of dorsal seta of pedicel:

(0) shorter than basal flagellomere;

(1) same length as basal flagellomere.

4. Shape of face:

(0) nearly vertical, essentially flat;

(1) distinctly protruding;

(2) slightly protruding.

5. Face, setulae on medial area and lower facial margin (oral margin):

(0) present;

(1) absent.

6. *Density of facial setulae on medial area and lower margin:

(0) sparsely setulose;

(1) densely setulose.

Comments. Contingent on character 4, state 0.

7. Face, length of lateral facial setae:

(0) short and undistinguishable from facial setae;

(1) longer and stronger than facial setae.

Comments. Contingent on character 4, state 0.

8. Orientation of long lateral facial setae:

(0) curved anteroventrally;

(1) curved lateroventrally;

(2) curved laterodorsally.

9. Facial row of setulae near parafacial margin:

(0) present;

(1) absent.

10. Relative height of facial projection or hump:

(0) less than half height of head;

(1) half height of head;

(2) higher than half height of head.

Comment. The height is measured from the inferior margin of the face to dorsum of hump.

11. Width of frons:

(0) wider than long;

(1) as wide as long.

12. Shape of frontal vitta:

(0) triangular;

(1) subquadrate.

13. Interfrontal seta:

(0) absent;

(1) present.

Comment. This seta is elongated, well developed, and cruciate, and is present in some genera of Ephydrini.

14. Ocellar seta:

(0) present;

(1) absent;

15. Setulae along anterior margin of frontal vitta (mesofrons):

(0) absent;

(1) present.

Comment. These setulae are small but evident and distinct from the microtomentum.

16. Microtomentose vestiture of frontal vitta:

(0) absent;

(1) present.

Comments. When the microtomentum is absent, the frontal vitta is bare, shiny; microtomentose frontal vitta is dull.

17. Arrangement of ocelli:

(0) equally distant from each other, as an equilateral triangle;

(1) as an isosceles triangle.

Comment. When the ocelli are arranged in an isosceles triangle, the anterior ocellus is farther away from the posterior ocelli than the distance between the posterior ocelli.

18. Length of ocellar seta:

(0) seta long, subequal to fronto-orbital setae;

(1) seta short, half of fronto-orbital seta.

Comment. This character is contingent on character 16, state 0.

19. Shape of eye:

(0) round or nearly so (Eye ratio 0.9 to 1.1);

(1) conspicuously wider than high, usually obliquely oriented (Eye ratio > 1.1);

(2) conspicuously higher than wide than high (Eye ratio < 0.9).

20. Number of fronto-orbital setae:

(0) 2;

(1) 1;

(2) 3;

(3) 4 or more;

(4) secondarily reduced in length.

Comment. This is a multistate character that is treated as nonadditive. Only well-developed fronto-orbital setae are counted; i.e., length subequal to length of medial and lateral vertical setae.

21. Orientation of fronto-orbital setae:

(0) proclinate and/or reclinate;

(1) lateroclinate.

Comment. Non-Ephydrinae shore flies usually have proclinate or reclinate fronto-orbital seta.

22. Paravertical seta, length:

(0) short, only slightly longer than longer postocellar setae;

(1) long, subequal to ocellar seta.

Comments. Species of the genera Paracoenia, Calocoenia and Cirrula (Ephydrini) share a long paravertical seta.

23. Size of subcranial cavity:

(0) relatively small;

(1) large, sometimes gaping.

24. Posterior fronto-orbital seta, position:

(0) inserted closer to anterior fronto-orbital seta than to medial vertical seta;

(1) inserted closer to medial vertical seta than to anterior fronto-orbital seta.

25. Genal seta:

(0) present;

(1) absent.

26. Genal seta, length:

(0) long, conspicuous;

(1) short, only slightly larger than genal setulae.

Comment. This character is contingent on character 25, state 0.

27. Genal height:

(0) low (gena to eye ratio < 0.25);

(1) moderately high (gena to eye ratio 0.25 to 0.50);

(2) high (gena to eye ratio > 0.50).

28. Facial convexity, shape of arching:

(0) mostly vertical, somewhat flat, shallowly protuberant;

(1) vertically arched, shield-like;

(2) overtly protuberant;

(3) transversely arched.

Comment. This character is related to character 23.

29. Palpus shape:

(0) claviform;

(1) slender, essentially parallel sided, not claviform.

30. Lacinia, distal portion, projection, shape, anterior view:

(0) straight;

(1) T-shaped.

31. Cibarium, lateral projections:

(0) present;

(1) absent.

32. Cibarium, lateral projections, size:

(0) short, same length as ventral projection;

(1) long, longer than ventral projection.

33. Labellum, sclerite 2, length:

(0) more or less as long as width of labellum, not overlapping prementum;

(1) longer than width of labellum, overlapping prementum.

34. Mediproboscis, lateral sclerite:

(0) absent;

(1) present.

Thorax

35. Thorax, vestiture, coloration:

(0) unicolorous or with gradual changes in coloration;

(1) distinctly bi- or tricolored, with stripe patterns.

36. Prosternum, setulae:

(0) present;

(1) absent.

37. Setulae of propleuron

(0) absent;

(1) present.

38. Presutural dorsocentral setae, number of pairs:

(0) 0;

(1) 1.

Comment. Only long presutural dorsocentral setae are counted;length of these is subequal to postalar seta.

39. Postsutural dorsocentral setae, number of pairs:

(0) 2 (0+2 or 1+2; typical of most genera of Scatellini);

(1) 1 (0+1; posterior seta just slightly larger than anterior setulae of track);

(2) 1 (0+1; posterior seta well developed);

(3) 3 (0+3);

(4) 3 (1+3);

(5) 4 (1+4);

(6) 3 (2+3).

Comment. Only postsutural dorsocentral setae are considered; posterior dorsocentral seta often displaced laterally from alignment of anterior setae.

40. Proepisternal macrosetae:

(0) absent;

(1) present.

41. Postpronotal setation:

(0) 1-3 setae plus scattered setulae;

(1) with a few setulae.

42. Presutural supra-alar seta:

(0) present;

(1) absent.

43. Postsutural supra-alar seta:

(0) present;

(1) absent.

44. Postsutural supra-alar seta, length:

(0) smaller than postalar seta;

(1) as long as postalar seta.

45. Posterior notopleural seta, position:

(0) inserted at same level as anterior seta;

(1) insertion distinctly elevated above level of anterior seta.

46. Relative strength of notopleural setae:

(0) anterior seta as long as posterior seta;

(1) anterior seta shorter than posterior seta.

Comment. This is an autapomorphy for the genus Psilephydra.

47. Anepisternum, anterodorsal corner, seta:

(0) indistinguishable from surrounding setae;

(1) one strong, distinct seta dorsally curved.

48. Acrostichal setae, arrangement:

(0) forming 2 rows;

(1) scattered, random setae, not forming a row.

49. Acrostichal setae, extension of rows:

(0) rows extended to scutellum;

(1) rows not extended to scutellum.

Comment. This character is contingent on character 48, state 0.

50. Sutural acrostichal setae, length:

(0) short, same length as other acrostichal setae;

(1) longer than other acrostichal setae.

51. A well-developed pair of prescutellar acrostichal setae:

(0) present in both sexes;

(1) absent in both sexes;

(2) male absent, female present.

Comment. In some genera, such as Cirrula, the type species, C. gigantea, does not have prescutellar acrostichal setae, but other included taxa, such as C. hians, does.

52. Intrapostalar seta:

(0) present;

(1) absent.

53. Intrapostalar seta, length:

(0) small seta, much smaller than postalar seta;

(1) long seta, slightly smaller than postalar seta.

Comment. This character is contingent on character 52, state 0.

54. Intra-alar seta:

(0) absent;

(1) present.

55. *Intra-alar seta, arrangement:

(0) scattered setae;

(1) aligned with row of intra-alar setae.

Comments. Contingent on character 54, state 1.

56. Prescutellar acrostichal seta, length:

(0) short, same length as other acrostichal setae;

(1) longer than other acrostichal setae.

57. Wing development:

(0) macropterous;

(1) stenopterous;

(2) micropterous.

58. Wing infuscation:

(0) essentially hyaline, infuscation extremely faint;

(1) infuscate, often darker on anterior margin and lighter on posterior margin.

59. Wing, white spots:

(0) absent;

(1) present, pale to conspicuous.

60. Wing, white spots, density:

(0) wing lacking white spots;

(1) wing with many white spots;

(2) wing with few white spots.

61. Costal vein, length:

(0) long, extended to vein M₁;

(1) short, extended to vein R₄₊₅.

62. Costal vein, subcostal break, overlapping:

(0) Costal vein continuous at subcostal break;

(1) Costal vein slightly to deeply overlaps itself at subcostal break, sometimes looking like a spur.

63. Crossvein r-m, position:

(0) crossvein r-m just posterior or slightly distad of subcostal break;

(1) crossvein r-m distinctly basal to subcostal break;

(2) crossvein r-m distinctly distal to subcostal break.

64. Crossvein dm-m with infuscate spot:

(0) absent;

(1) present.

65. Costal vein spines along anterior margin:

(0) present;

(1) absent.

66. Scutellar seta, number of pairs:

(0) 2;

(1) 3.

Comment. When the number of pairs of scutellar seta is three, the extra pair is always located at the base of the scutellum.

67. Medial scutellar seta, length:

(0) long, at least 2/3 of apical seta;

(1) short, at most 1/2 of apical seta.

68. Anepisternal setae, length:

(0) small setae in addition to a longer, strong seta;

(1) long setae in addition to a longer, strong seta.

Comment. The anepisternum always bears a long, well-developed anepisternal seta.

69. Katepisternal seta, length:

(0) long, well developed;

(1) short, weakly developed;

(2) lacking or greatly reduced, setulae-like.

Comment. Number 1 is an autapomorphy for the tribe Dagini and number 2 for Paracoenia (Thiomyia).

70. Setulae of hindcoxal strap:

(0) absent;

(1) present.

71. Male midfemur, posteroventral side, setae, shape:

(0) setae slender, not in a comb-like row;

(1) comb-like row of stout setae.

Comment. An autapomorphy for Paracoenia (Paracoenia).

72. Male forefemur, anteroventral side, setae, shape:

(0) stout;

(1) slender.

Comment. Also referred to as ^“wart-like structures” (Olafsson 1991).

73. Tarsal claws, shape:

(0) conspicuously curved;

(1) near straight.

74. Pulvilli:

(0) conspicuous below each claw;

(1) absent or greatly reduced.

Abdomen

75. Abdomen, microtomentum:

(0) present;

(1) absent.

Comments. When the microtomentum is absent, the abdomen appears polished, shiny.

76. Sternite 1:

(0) present;

(1) absent.

77. Number of well-developed sternites of male after sternite 4:

(0) 2;

(1) 1;

(2) 0.

Comment. ^[2] Previous authors proposed that the sternite 5 is absent and only sternite 6 is present (Olafsson 1991).

78. Male sternites 3 and 4, setae, shape:

(0) slender;

(1) short, spine-like setae.

79. Female sternites, form:

(0) square to rectangular-shaped, relatively wide;

(1) distinctly narrow sternites.

80. Tergite 5 of male, posterolateral projection:

(0) absent;

(1) present.

81. Epandrium or epandrium/surstyli, opening:

(0) present;

(1) absent.

Comment. Since the epandrium can be indistinguishably fused with surstyli or the latter are absent, we refer to them as “epandrium or epandrium/surstyli” (see character 85).

82. Epandrium or epandrium/surstyli, opening, size:

(0) narrow opening below the cerci;

(1) wide opening above the cerci;

(2) wide opening below the cerci.

83. Epandrium, ventral projection:

(0) present;

(1) absent.

84. Surstylus, fusion with epandrium:

(0) distinctly separate from epandrium;

(1) fused to the epandrium but distinguishable as surstylus;

(2) surstyli indistinguishable from epandrium or absent.

85. Surstyli, anterolateral projection:

(0) absent;

(1) present.

86. Surstylus or surstylus/epandrium, number of pieces:

(0) surstylus a single piece;

(1) surstylus in two pieces.

87. Epandrium or epandrium/surstylus, shape in posterior view:

(0) roughly ellipsoid to subquadrate;

(1) ovoid.

88. Epandrium, ventral margin, shape:

(0) straight or slightly convex;

(1) incised medially forming 2 lateral, lobate processes.

89. Aedeagal shape:

(0) quill-like structure;

(1) keel-like structure;

(2) long and thin, tubular;

(3) shoe-like structure;

(4) large and bulky tube;

(5) “Diedrops aedeagus”.

Comment. ^[3] The aedeagus in Diedrops is uniquely shaped, and we propose a separate state for this condition.

90. Aedeagus, constitution:

(0) sclerotized structure (apparently the basiphallus) only, lacking a membranous distiphallus;

(1) with a sclerotized basiphallus and a membranous distiphallus that is invested with short, sharp scales or scale-like thorns.

91. Aedeagus, ventral process:

(0) present;

(1) absent.

92. Ejaculatory apodeme:

(0) absent;

(1) present.

93. Ejaculatory apodeme, shape:

(0) L-shaped, flattened dorsoventrally structure;

(1) crescent shaped, laterally flattened.

Comments. Contingent on character 92, state 1.

94. Phallapodeme:

(0) present;

(1) absent.

95. Phallapodeme, shape:

(0) a laterally flattened bow, often with an extended keel;

(1) flattened dorsoventrally, usually with 2 lateral projections, rod-like, lacking a keel.

Comment. This character is contingent on character 94, state 0.

96. Gonites and hypandrium, fusion:

(0) complete as a single structure, i.e., gonites and hypandrium fused;

(1) separated into a sclerite hypandrium and lateral structures representing gonites.

Comment. The hypandrium is considered fused with gonites within Ephydrinae, and the anterior arms of the gonite/hypandrium is called “gonal arch”.

97. Hypandrial shape:

(0) a straight sclerite hypandrium;

(1) a bifurcate sclerite hypandrium;

(2) a U-shaped broad hypandrium.

^[4] referred as “neohypandrium” to Scatophila (Zatwarnicki and Mathis 1994).

98. Gonal arch, arms, fusion:

(0) arms separated;

(1) arms fused.

99. Gonal arch and phallapodeme, fusion:

(0) separated, not fused;

(1) fused.

100. Posterodorsal arm of gonite:

(0) present;

(1) absent.

101. Posterodorsal arm and gonal arch, shape:

(0) bulky dorsal arm;

(1) large, more like a flap.

Comments. Contingent on character 100, state 0.

102. Female sternite 8, setae, length:

(0) same length as other setae;

(1) bearing prominent setae.

103. Female sternite 9/subanal plate, setae, development:

(0) bearing one pair of strong setae;

(1) slender, indistinguishable from surrounding setae.

104. Female cerci, development of setae:

(0) slender, indistinguishable from surrounding setae;

(1) bearing one long, strong, prominent seta, inserted posteroventrally;

(2) a long, slender seta inserted posteroventrally.

105. Female sternite 7:

(0) present;

(1) absent.

106. Female sternite 7, fusion:

(0) 1 sclerite;

(1) 2 sclerites.

Comment. This character is contingent on character 105, state 0.

107. Female sternite 8, number:

(0) 1 sclerites;

(1) 2 sclerite.

108. Female sternite 8, shape:

(0) 2 sclerites, crescent-shaped;

(1) 2 sclerites, subquadrate.

Comment. This character is contingent on character 107, state 1.

109. Female tergite 8:

(0) tergite complete, like an arch;

(1) tergite incomplete, only 2 sclerites laterally.

Comment. ^[6] The female abdomen of Brachydeutera only has seven segments + cerci, instead of the usual eight in Ephydrinae, and we are assuming that this state is not applicable to Brachydeutera.

110. Female ventral receptacle, operculum:

(0) present;

(1) absent.

111. Female ventral receptacle, shape of operculum:

(0) operculum helmet-like or mushroom-like, rounded to trapezoidal, extended process not longer than width of operculum;

(1) operculum relatively reduced, tube-like, extended process elongate twice or longer than width of operculum;

(2) tiny, flat, extended process elongate.

Comment. This character is contingent on character 110, state 0. State 2 is an autapomorphy for Notiocoenia.

112. Ventral receptacle, size of operculum:

(0) large and well developed, covering the extended process;

(1) small, not covering the extended process.

Comment. This character is contingent on character 112(0).

113. Larval prolegs:

(0) absent;

(1) present;

(2) secondarily reduced or absent.

Edited by

• Editorial responsibility
  Alessandra Rung

Publication Dates

• Publication in this collection
  20 Jan 2025
• Date of issue
  2025

History

• Received
  04 July 2024
• Accepted
  19 Nov 2024