A review of the Neotropical species of the shore-fly genera Orasiopa and Pectinifer ( Diptera : Ephydridae )

Species of two genera of the tribe Discocerinini from the Neotropics are reviewed with an emphasis on the fauna from Brazil. The two species, Orasiopa (Reymontopa) mera (Cresson, 1939) and Pectinifer aeneus (Cresson, 1918), are described, illustrated and new occurrence data are provided. Phylogenetic relationships of these two genera into the tribe are discussed. To facilitate identification of these species, we have included diagnoses of the Discocerinini and both genera and have also provided an annotated key to the New World genera in this tribe. We have also provided illustrations, photographs, and scanning electron micrographs of external structures and of structures of the male terminalia for included species.


MATERIAL AND METHODS
The terminology, with the exceptions noted in Mathis (1986) and Mathis & ZatWarnicki (1990a, 1990b), follows Mcalpine (1981).ZatWarnicki (1996) suggested that the pre-and postsurstylus correspond with the pre-and postgonostylus and that the subepandrial sclerite is the same as the medandrium.We use the term basal flagellomere for the large antennomere beyond the pedicel.We prefer this term over "first flagellomere" as there may be more than one flagellomere involved, and basal does not imply a number or numbers.We likewise do not use "postpedicel" (stuckenberg 1999) for this antennomere because at least the multisegmented arista is beyond the pedicel in addition to the large antennomere, and postpedicel is thus ambiguous and lacking in precision.
Because specimens are small, usually less than 2.60 mm in length, study and illustration of the male terminalia and determination of species required use of a compound microscope.
Dissections of male terminalia were performed following clausen & cook (1971) andgriMaldi (1987).Abdomens were removed with microforceps and macerated in a sodium hydroxide solution.Cleared genitalia were then neutralized in dilute glacial acetic acid and transferred to glycerin for observation, description, and illustration.The dissected abdomen was placed in a plastic microvial filled with glycerin and attached to the pin supporting the remainder of the insect from which it was removed.
Photographs of specimens, especially heads, were taken with a Visionary Digital System.The images series obtained were combined by Zerene Stacker © and edited with Adobe Photoshop © .
The species descriptions are composite and not based solely on holotypes.Head and two venational ratios used in the descriptions were based on three specimens (largest, smallest, and one other) as follows: gena-to-eye ratio -genal height (immediately below maximum eye height)/eye height; costal vein ratio -the straight line distance between the apices of R 2+3 and R 4+5 /distance between the apices of R 1 and R 2+3 ; M vein ratio -the straight line distance along vein M between crossveins dm-cu and r-m/distance apicad of dm-cu.
Distribution maps were made using ESRI ArcView © GIS 3.2.Geographical coordinates were obtained from specimen labels.If coordinates were unavailable, they were culled from gazetteers and maps.
For perspective and to facilitate genus-group and species-group recognition, the tribe Discocerinini is diagnosed and a key to included genera is provided.
Remarks.Starting with cresson (1925), who first described Discocerinini, and including all researchers of the family until Mathis & Zuyin (1989), the diagnoses, descriptions, and catalogs of this tribe included some taxa that are not closely related phylogenetically, rendering the tribe polyphyletic.Mathis & Zuyin (1989)    Diagnosis.Orasiopa is distinguished from other genera of Discocerinini by the following combination of characters: Small to moderately small shore flies, body length 2.20-3.60 mm; generally densely microtomentose, dull species.Head.Frons lacking orbital setae.Face moderately prominent at level of dorsal facial seta; antennal grooves generally weakly defined ventrally; face bearing one series of setae and one series of fine setulae; facial setae 4, dorsal setae not arising from shiny papilla, lacking dorsoclinate seta at lower lateral extremity; parafacial narrow throughout length, lacking setulae; gena short (genato-eye ratio 0.06-0.22).Eye oval, moderately conspicuously microsetulose, bearing distinct interfacetal setulae.Thorax.Single presutural and postsutural supra-alar setae evident; acrostichal setae present; notopleuron bearing several setulae in addition to 2 larger, ventral setae.Wings brown infumate or transparent; costa bearing 5-6 long, dorsal setae between humeral and subcostal breaks.Forefemur normally developed, lacking row of short, stout setae along posteroventral surface; hindtibia lacking a preapical, ventral, spur-like seta.Abdomen.Tergites unicolorous, lacking pale colored areas laterally; tergite 4 of male longer than tergite 3. Male terminalia.Epandrium complete posteriorly, although sometimes attenuate in dorsal view, ellipsoidal in outline, generally more broad anteriorly, setulose mostly in anterior area; cerci not fused with epandrium, elongate, moderately covered with setae; gonites fused with hypandrium with one setula or without setulae, in dorsal view band-like, in lateral view not distinguishable from hypandrium; aedeagus symmetrical, moderately elongate, in dorsal view triangular or rectangular with broadly rounded anterior margin, or asymmetrically turned anterolaterally, posterior Orasiopa is essentially an Old World genus that is widespread in the Australasian/Oceanian and Oriental Regions, as well as Japan and the Seychelles.Orasiopa mera (Cresson, 1939) is found in the New World, where it has apparently been widely introduced, perhaps through human transport, with some subsequent dispersal.This is the first record of Orasiopa from Brazil, Costa Rica, and the United States, as well as many island nations of the Caribbean (Barbados, Cuba, Grenada, Jamaica, Saint Vincent, and Trinidad and Tobago).Diagnosis.This subgenus is distinguished from the nominotypical subgenus by the following combination of characters: Species generally compact; thorax and abdomen dark brown or black.Head.Antenna dark brown or black; arista bearing usually 7-11 dorsal rays; palpus brownish or black.Proboscis with 11 pseudotracheae.Thorax.Knob of halter white; legs mostly dark brown to black.Abdomen.Male terminalia asymmetrical; epandrium with setation over entire length.
Type material (examined).The holotype female of Discocerina mera Cresson is labeled "Formosa Sauter/Takao 1907.17   Natural history.Nearly all specimens collected in the New World are from the littoral physiographic province, often in maritime habitats where saline conditions prevail.
Remarks.This species is distinguished from its Old World congeners by the following combination of characters: body generally black except tarsi; vertical series of facial setae three or more; face entirely black, lacking vertical stripes, sparsely invested with whitish microtomentum; parafacials narrow, lacking setulae, black, concolorous with face; frons black but with sparse investment of whitish microtomentum, especially on anterior margin, lacking metallic blue or green stripes; legs, including coxae, black except for yellowish tarsi; mesonotum sparsely microtomentose, subshiny; postsutural supra-alar seta present; and anterior notopleural seta inserted in anterior notopleural angle.This species was originally described from specimens collected in the Orient (Taiwan and Japan), and it has been recorded from the Caribbean (Mathis 1997), which was then considered to be a rather remarkable range extension for any shore-fly species.This is the first report of this species from Brazil and Costa Rica, as well as many other islands of the Caribbean.We suspect that its occurrence in the New World is the result of an introduction, perhaps multiple introductions, with some subsequent dispersal.
Pectinifer Cresson, 1944Pectinifer Cresson, 1944: 4 Diagnosis.Pectinifer is distinguished from other genera of Discocerinini by the following combination of characters: moderately small shore flies, body length 2.40 mm; generally sparsely microtomentose, subshiny species.Head.Frons bearing orbital seta.Face rather prominent at level of dorsal facial seta; antennal grooves generally distinctly defined ventrally; face lacking secondary series of setae; facial setae 4-5, dorsal setae not arising from shiny papilla, lacking an dorsoclinate seta at lower lateral extremity; parafacial narrow throughout length, lacking setulae; gena generally low.Eye generally oval, moderately conspicuously microsetulose, bearing interfacetal setulae not discernible by light stereomicroscope.Proboscis with 10 pseudotracheae; cibarium with 6 medial sensillae arranged in a transverse row and 9 moderate posterior sensillae.Thorax.Presutural supra-alar seta well developed; postsutural supra-alar setae reduced or lacking; acrostichal setae present; notopleuron bare of setulae.Wings hyaline; costa bearing 4-5 long, dorsal setae between humeral and subcostal breaks.Forefemur slightly enlarged, bearing distinct row of stout, short setae along apical half of posteroventral surface; hindtibia lacking a preapical, ventral, spur-like seta.Abdomen.Tergites usually unicolorous, lacking pale colored areas laterally; tergite 4 of male longer than tergite 3. Male terminalia: Epandrium complete posteriorly, in dorsal view U-shaped with long arms, in outline 1.5 times as long as wide, in lateral view folded down anterolaterally; cerci separate from epandrium, elongate, in lateral view tapered apically, 5 times as long as wide; gonite separate from hypandrium, elongate with subapical setulae, in dorsal view slightly arcuately deflected inward, in lateral view broadened centrally, irregularly tapered to apices; aedeagus in dorsal view rectangular with rounded anterior margin and basal 1/4 margin roundly incised, in lateral view irregularly trapezoidal with anterodorsal appendix of 3/4 length of aedeagus; hypandrium in dorsal view U-shaped with posterolateral arms with length 3/4 of the base, in lateral view slightly depressed centrally; phallapodeme separate from aedeagus, in dorsal view as wide as 1/3 of aedeagus, in front of hypandrium broadened triangularly, ventral section as wide as 1/3 of dorsal, apically slightly broadened, obtuse, in lateral view irregularly triangular, surrounding aedeagus posteroventrally, anterior margin sinuous forming protrusion ventrally; ejaculatory apodeme absent.Ventral receptacle with regular operculum, stalk -shaped with small basal bands.
Phylogenetic considerations.Pectinifer is currently placed in the Diclasiopa group of genera, also including Diclasiopa, Ditrichophora, and Hecamedoides (ZatWarnicki & Mathis 2001, ZatWarnicki et al. 2016).The Diclasiopa group is characterized by an elongated gonite that is tapered apically and bears at most two dorsal and typically one subapical and ventral setula.Remarks.This genus is currently monotypic and is only known from the New World tropics (Mathis & ZatWarnicki 1995, ZatWarnicki & Mathis 2001, ZatWarnicki et al. 2016).
Pectinifer aeneus (Cresson, 1918)  Diagnosis.This genus and its monotypic species are distinguished from related taxa by the following combination of characters: Small to moderately small shore flies (Fig. 19), body length 1.65-2.65 mm.Head (Figs. 17-18): Face bearing two rows of 3-4 spots of silvery white microtomentum between the slightly produced midventrally and the parafacial; gena-to-eye ratio 0.08-0.12.Thorax.Notopleuron lacking setulae (only 2 large setae present); prescutellar acrostichal seta lacking.Costal vein ratio 0.71-0.73;M vein ratio 0.58-0.60.Foreleg entirely dark brown, mid and hind tarsi yellow; forefemur slightly enlarged, bearing a distinctive row of short, stout setae along apical half of posteroventral surface.Abdomen: Male terminalia (Figs.20-23): epandrium complete posteriorly, in dorsal view U-shaped with long arms, in outline 1.5 times as long as wide, in lateral view folded down anterolaterally; cerci separate from epandrium, elongate, in lateral view tapered apically, 5 times as long as wide; gonite separate from hypandrium, elongate with subapical setulae, in dorsal view slightly arcuately deflected inward, in lateral view broadened centrally, irregularly tapered to apices; aedeagus in dorsal view rectangular with rounded anterior margin and basal 1/4 margin roundly incised, in lateral view irregularly trapezoidal with anterodorsal appendix of 3/4 length of aedeagus; hypandrium in dorsal view U-shaped with posterolateral arms with length 3/4 of the base, in lateral view slightly depressed centrally; phallapodeme separate from aedeagus, in dorsal view as wide as 1/3 of aedeagus, in front of hypandrium broadened triangularly, ventral section as wide as 1/3 of dorsal, apically slightly broadened, obtuse, in lateral view irregularly triangular, surrounding aedeagus posteroventrally, anterior margin sinuous forming protrusion ventrally; ejaculatory apodeme absent.Natural history.Although widespread in the Neotropics, specimens are seldom abundant at a locality.The site on the West Indian island of Saint Lucia where we collected nearly 25 specimens was where a cart load of cabbage had been overturned on a mountainous road a few days earlier and the cabbage leaves were beginning to decompose.We simply swept our nets immediately over the pile of deposing vegetation to collect the series.About a week later, we returned to the site, hoping to collect more specimens but without any success.By this time the rotting pile of cabbage had been reduced to an amorphous mass.
Remarks.Being the only included species in Pectinifer, the generic diagnosis serves to distinguish this species from others in the tribe.
then recharacterized Discocerinini based on synapomorphies, under which Mathis & ZatWarnicki (1995) included eight genera and 143 species in their world catalog.ZatWarnicki & Mathis (2001) added two genera, Galaterina Zatwarnicki & Mathis, 2001 and Orasiopa, and altered the status of some subgenera in their phylogenetic study of the tribe.More recently, Mathis & ZatWarnicki (2013) proposed Facitrichophora for four Neotropical species that were described in the same paper.As currently characterized (herein and in ZatWarnicki et al. 2016), Discocerinini is one of the richest tribes within the family Ephydridae with 213 species in 13 genera and two subgenera.Two genera are monotypic and have relatively localized distributions: Galaterina in the Solomon and Andaman Islands and Pectinifer limited to the Neotropics (herein).Other genera are more diverse and widespread.Aquachasma Zatwarnicki (24 species), Facitrichophora (4 species), Hydrochasma (10 species), and Polytrichophora (nominotypical subgenus) (21 species) are found in the New World.The distributions of Lamproclasiopa (19 species) and Orasiopa (15 species) extend from the New World into the Australasian and Oriental Regions.Diclasiopa Hendel, 1917 (4 species), Gymnoclasiopa Hendel, 1939 (27 species), Hecamedoides Hendel, 1917 (26 species) and Ditrichophora Cresson, 1924 (35 species) have been recorded from all Regions except the Neotropics.Two genera, Discocerina (18 species) and Sklodowskora (10 species), are essentially cosmopolitan.The two genera that we treat herein, Orasiopa and Pectinifer, are in different groups of genera within Discocerinini (ZatWarnicki & Mathis 2001, ZatWarnicki et al. 2016), and the composition and phylogenetic relationships of these two groups are discussed under each genus.
surface wrinkled or covered by small setulae dorsally; hypandrium in dorsal view U-shaped with broadly rounded base and slightly broadened lateral arms, in lateral view band-like; phallapodeme weakly developed, separate from aedeagus, in dorsal view flat or Y-shaped with triangular base, in lateral view band-like without ventral projection or irregularly trapezoidal; ejaculatory apodeme absent.Phylogenetic considerations.The former Discocerina group of genera (Discocerina, Galaterina, Hydrochasma, Lamproclasiopa, Orasiopa, and Polytrichophora) is the best supported clade within Discocerinini and is characterized by two synapomorphies: (1) notopleuron bearing setulae; (2) gonites either elongated without an anterior projection or wholly reduced (ZatWarnicki & Mathis 2001).However, this clade was recently divided into two groups, the Lamproclasiopa and Discocerina groups (ZatWarnicki et al. 2016), and Orasiopa is placed in the Lamproclasiopa group.ZatWarnicki et al. (2016) confirmed the monophyly of Lamproclasiopa group by a single character: base of palpal setae papilla-like (character 13 in ZatWarnicki et al. 2016).The monophyly of the Orasiopa + Galaterina clade is supported by mouthparts having a larger number of pseudotracheae (at least 8).According to ZatWarnicki et al. (2016) the diagnostic characters for Orasiopa are: facial series of setae 3-4, 13-15 medial sensillae, gonites fused with hypandrium, and phallapodeme weakly developed.ZatWarnicki et al. (2016) recently divided Orasiopa into two subgenera, with the nominotypical subgenus being distinguished by the following synapomorphies: proboscis with 8 pseudotracheae and knob of halter dark.The new subgenus they proposed, Reymontopa, is distinguished by three characters: (1) lacking epandrial setation on the dorsal section; (2) aedeagus and phallapodeme asymmetrical; and (3) mouthparts with 11 pseudotracheae.Remarks.ZatWarnicki & Mathis (2001) described Orasiopa and shortly thereafter ZatWarnicki (2002) revised the genus.
(2016)  in this subgenus, only O. mera(Cresson)  occurs in the New World.The other congeners of both subgenera occur primarily in the Old World tropics.ZatWarnicki et al. (2016) noted that this subgenus was named after a famous Polish novelist and Nobel laureate, Wladyslaw Reymont.
Pectinifer forms a separate clade within the Diclasiopa group and is characterized by the following three autapmorphies: (1) Face metallic shiny bearing white microtomentose spots laterally; (2) forefemur slightly enlarged and bearing a distinctive row of stout, short setae along the apical half of the posteroventral surface; (3) 10 pseudotracheae (convergence with Galaterina).ZatWarnicki et al. (2016) proposed the latter character based on their comparative study of mouthparts within Discocerinini.Distribution.See "Distribution" of the only included species below.