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A new enigmatic species of broad-nosed weevil endemic to Brazil and its phylogenetic placement within the tribe Naupactini (Coleoptera: Curculionidae: Entiminae)

Abstract

A new species of Naupactini (Curculionidae: Entiminae) endemic to Brazil, Espírito Santo and Minas Gerais states, is herein described. It resembles the monotypic genus Hadropus Schoenherr in its general appearance, particularly in the shape of the elytra, and the color of the vestiture, but the results of a cladistics analysis herein conducted suggest that it belongs to the genus Stenocyphus Marshall. This genus ranges in São Paulo, Rio de Janeiro and Espírito Santo, mainly in the Atlantic forest of Brazil, and includes three other species. Stenocyphus costae sp. nov., distinguishes from the remaining species of Stenocyphus by the green iridescent scaly vestiture, having long stiff setae on the two pairs of elytral tubercles; the more slender rostrum; the shorter antennae; the convex disc of the pronotum; and the shorter and broader elytra. This paper includes a cladogram of the Naupactini genera showing the phylogenetic position of the new species, its complete description, photographs of male and female habitus, line drawings of genitalia of both sexes, and a key of the Stenocyphus species.

Key-Words.
Hadropus; Neotropical region; South America; Stenocyphus

INTRODUCTION

The Neotropical genera Hadropus Schoenherr, 1826 and Stenocyphus Marshall, 1922 (Curculionidae, Entiminae, Naupactini) share several morphological characters, such as the presence of elytral tubercles and the disc of the elytra elevated towards the beginning of the declivity (humped elytra); the vestiture composed of scales and coarse setae; the tibiae lacking rows of denticles along the inner margin or with minute denticles; and the corbels of the metatibiae well-developed, covered with scales or scale-like setae. Hadropus is a monotypic genus that ranges in Paraguay and Brazil, mainly in the Chacoan and Parana subregions (del Río & Lanteri, 2011del Río, M.G. & Lanteri, A.A. 2011. Taxonomic revision of the genus Hadropus Schoenherr (Coleoptera: Curculionidae) with comments on infraspecific variation. Transactions of the American Entomological Society, 137(344): 307-315.), and Stenocyphus is endemic to Brazil, and is mainly distributed along the Atlantic forest, from São Paulo to Espírito Santo (del Río & Lanteri, 2013del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43.). Mixed in the series of Hadropus albiceris Germar, we found some specimens which are similar to this species in the characters of the vestiture and shape of the elytra, but differentiate in some diagnostic characters at generic level, such as those of the rostrum and shape of the spermatheca (see del Río & Lanteri, 2011del Río, M.G. & Lanteri, A.A. 2011. Taxonomic revision of the genus Hadropus Schoenherr (Coleoptera: Curculionidae) with comments on infraspecific variation. Transactions of the American Entomological Society, 137(344): 307-315.). We concluded that these specimens correspond to a new species, and in order to test its generic position we undertook a cladistics analysis based on morphological characters.

The objectives of this contribution are to describe the new species, to illustrate its diagnostic characters, and to analyze its phylogenetic position within the tree of the Naupactini, to decide about to its correct generic placement.

MATERIAL AND METHODS

Specimens of the new species are very scarce in entomological collections, and they would be rare in nature. This study was based upon the examination of specimens borrowed from the following institutions: AMNH: American Museum of Natural History, New York, USA. Lee Herman; DZUP: Departamento de Zoologia, Universidade Federal do Parana, Curitiba, PR, Brazil. Germano Rosado-Neto; MLPC: Museo de La Plata, Buenos Aires, Argentina. María Guadalupe del Río; MZSP: Museu de Zoologia da Universidade do São Paulo, SP, Brazil. Sergio Vanin.

Dissections of female and male genitalia were made according to standard entomological techniques. Characters of the genitalia were drawn using a camera lucida adapted to a stereoscopic microscope Nikon SMZ800. Measurements were taken with an ocular micrometer attached to this microscope. The abbreviations used in the description are as follows: L = maximum length; W = maximum width; WR = width of rostrum measured across apex (excluding scrobes); WF = width of forehead between anterior margins of eyes.

The key for the species of Stenocyphus was expanded from that of del Río & Lanteri (2013del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43.).

Phylogenetic analysis

The morphological characters and character states used for this phylogenetic analysis were listed in Lanteri & del Río (2017Lanteri, A.A. & del Río, M.G. 2017. Phylogeny of the tribe Naupactini (Coleoptera: Curculionidae) based on morphological characters. Systematic Entomology, 42(2): 429-447.) (Table S1). The list consisted of 100 discrete morphological characters of the adults, including 78 from the external morphology and 22 from the female and male genitalia.

A data matrix herein analyzed includes 76 terminal taxa (72 for the ingroup plus four outgroups) and 100 morphological characters (Table S2). Character states unknown were scored with “?” and treated as missing data (Maddison, 1993Maddison, W.P. 1993. Missing data versus missing characters in phylogenetic analysis. Systematic Biology, 42: 576-581.). All characters were treated as non-additive and were analyzed under equal and implied weights (K = 45).

Searches were conducted using the “traditional search” algorithm of TNT (Goloboff & Catalano, 2016Goloboff, P.A. & Catalano, S. 2016. TNT version 1.5, including a full implementation of phylogenetic morphometrics. Cladistics, 32(3): 221-238.), with 300 random addition sequences, Tree Bisection and Reconnection (TBR) branch swapping, holding 20 trees during each replication. Clade stability was evaluated with 1000 replication Bootstrap (BT) (Felseinstein, 1985Felseinstein, J. 1985. Confidence limits on phylogenies: an approach using the Bootstrap. Evolution, 39: 783-791.). We provide the total length (L), the consistency index (CI) (Kluge & Farris, 1969Kluge, A.G. & Farris, J.S. 1969. Quantitative phyletics and the evolution of anurans. Systematic Zoology, 18: 1-32.) and the retention index (RI) (Farris, 1989Farris, J.S. 1989. The retention index and the rescaled consistency index. Cladistics, 5: 417-419.) of the most parsimonious trees (MP tree), calculated excluding the uninformative characters. Since more than one most parsimonious tree was obtained, we calculated a strict consensus tree among them (Goloboff & Farris, 2001Goloboff, P.A. & Farris, J.S. 2001. Methods for quick consensus estimation. Cladistics, 17: 26-34.).

RESULTS

Cladistic analysis

The heuristic search under equal weights yielded 35 equally parsimonious trees (L = 816 steps, CI = 0.21, RI = 0.54). In the consensus tree (Fig. 1), same as in the analysis under implied weights (k = 45), the new species is recovered in a clade including the species of Stenocyphus and Neoerycideus Hustache, 1938, mainly supported by the elytral disc ascending towards the beginning of the declivity (= humped) (char. 53.1) and the denticles of the inner margin of tibiae absent or minute (char. 70.0). The new species form a clade with the other three species of Stenocyphus (BT: 36), mainly supported by the presence of lateral rostral carinae (char. 11.1); gular angle slightly obtuse (char. 27.1); disc of pronotum with irregular foveae or large punctures (char. 48.1); elytra with tubercles on disc and declivity (char. 57.1); apex of median lobe of aedeagus rounded (char. 96.2) and endophallus of penis with flagellum (char. 98.1).

Figure 1
Strict consensus cladogram of 35 MP trees, showing the phylogenetic position of Stenocyphus costae sp. nov.

The three species of Stenocyphus (BT: 66) differentiated from the new species because they share the following characters: postocular constriction of head strong (char. 26.1); pronotum with a pair of lateral, longitudinal impressions (char. 42.1); uneven intervals of elytra (except suture) strongly convex, even intervals flat (char. 59.2); corbel at metatibial apex broad, squamose (char. 71.0); spermathecal corpus subcylindrical, slender (char. 89.0). Within this clade, S. bituberosus (Gyllenhal, 1833) is sister to S. sextuberosusdel Río & Lanteri, 2013del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43. (BT: 81).

The new species is not related to Hadropus, which is included in another clade of Naupactini where members also have humped elytra (see Fig. 1).

Systematics

Stenocyphus costae sp. nov.

(Figs. 2, 3)

Figure 2
Stenocyphus costae sp. nov. Paratype female: (A) head, frontal; (B) head, lateral; (C) habitus dorsal; (E) habitus lateral. Paratype male: (D) habitus dorsal. Scale bars: 1 mm.

Figure 3
Stenocyphus costae sp. nov. Female: (A) left antenna; (B) ventrites 1-5; (C) sternite VIII; (D) ovipositor, ventral; (E) spermathecae with spermathecal duct. Male: (F) aedeagus, terminal portion of tube, ventral; (G) aedeagus, lateral. Scale bars: A-B = 1 mm; C-G = 0.5 mm.

Type material: Holotype ♀ (DZUP): 10 mm long, with labels as follows: “Sta. Tereza-ES/ Brasil 07-XII-1964, C. Elias leg.” (dissected with genitalia in vial with glycerin). Paratypes: Same data as holotype (1♀ dissected with genitalia in vial with glycerin, MLP). Brazil, Espírito Santo, Tijuco Preto, Oct. 1948, A. Maller coll., Frank Johnson Donor (1♀, AMNH); Minas Gerais, Serra do Caraça, 27-XI a 05-XII-1972, Exp. Mus. Zool. (1♂ dissected with genitalia in vial with glycerin, MZSP).

Diagnosis:Stenocyphus costae sp. nov., is distinguished from the remaining species of Stenocyphus by the color of the scaly vestiture, iridescent green instead of cream or tan, and opaque; the longer and more slender rostrum; the shorter antennae, with scape almost reaching half of eyes, and funicular articles 3 to 7, 1.5-2.0× as long as wide; the strongly convex pronotum; the shorter elytra, with bisinuate anterior margin not projecting towards pronotum; the presence of two pairs of elytral tubercles covered with brown, stiff, long scale-like setae; the scutellum lacking scales; the narrow corbel of the metatibiae, covered with scale-like setae; the slender intercoxal portion of abdomen; the slightly shorter apodeme of sternite VIII and ovipositor; and the longer spermathecal duct.

Description: Species medium sized (female 8.7-10.0 mm; male 7.5 mm). Integument visible reddish-brown. Vestiture iridescent greenish, consisting on contiguous, small, subcircular, striate scales and suberect, coarse scale-like setae, stiff and long on the elytral tubercles (Figs. 2A-E).

Head (Figs. 2A-B): Rostrum slender, distinctly longer than wide at apex (L/WR: 1.35-1.55), sides convergent towards apex (WF/WR: about 1.5); dorsum flat; lateral carinae present; epistome strongly impressed, covered with small, scattered, subcircular scales; median groove linear, slightly exceeding hind margin of eyes; scrobes slightly curved downwards and directed towards base of eyes; gular angle about 120°.

Mouthparts: Mandibles covered with creamy scatter scales and coarse yellowish setae on external face; prementum subpentagonal, with external surface lacking setae. Eyes slightly drop-shaped, moderately convex; preocular impression triangular, elongate; postocular constriction indistinct. Forehead flat; vertex slightly convex. Antennae (Fig. 3A) short, ¼ of total body length, slightly exceeding pronotal margin, with setose scape and funicle; scape reaching half of eyes, about half length of funicle; funicular article 2, 2× as long as article 1, articles 3 to 7, 1.5-2× longer than wide; club acuminate, oval (L/W: 1.95-2.15).

Pronotum (Figs. 2C-D): As long as wide to slightly transversal (L/W: 1.05-1.25), sides divergent towards anterior ⅓ and almost subparallel on posterior ⅔, maximum width on anterior ⅓; disc slightly convex and elevated from base to apex, disc with irregular foveae and not well-defined median groove; anterior margin slightly curved anteriad; base bisinuate, with postero-lateral angles projected backwards.

Scutellum: Subtriangular, devoid of scales (Figs. 2C-D).

Elytra: Oval, short (L/W: 1.35-1.40), moderately high in lateral view, strongly ascending towards beginning of declivity (= humped) (Fig. 2E); base strongly bisinuate, not projecting towards pronotum; humeri strongly prominent, postero-laterally projected, without tooth; apex entire, subacute; apical declivity moderately abrupt (Figs. 2C-D); subapical callus distinct; punctures of striae medium sized (slightly narrower than intervals) with one oval scale on bottom; intervals wavy (with transversal undulations, or impressions and elevations); two pairs of tubercles present at beginning of declivity, the largest on interval 3, and the smallest on interval 5. Metathoracic wings well-developed.

Legs: Procoxae contiguous, 2× closer to anterior margin than to posterior margin of prosternum; protibiae strongly curved onwards, without denticles on inner face, and with erect thick setae on inner and outer face; pro- and mesotibiae with mucro and metatibiae without mucro; corbels of metatibiae well developed, covered with scale-like setae; dorsal comb slightly shorter than distal comb; tarsomere 2 as long as wide; tarsal claws free.

Abdomen (Fig. 3B): Intercoxal portion 1.30-1.35× broader than cavities of metacoxae; ventrite 2 about 1.4× as long as ventrites 3 + 4 (1.2× in males).

Female terminalia: Sternite VIII (Fig. 3C) subrhomboidal, slightly sclerotized, with V-shaped sclerotization and long apical setae; apodeme about 1.5× as long as plate of sternite. Ovipositor (Fig. 3D) about 0.6× as long as ventrites 1-5, slightly curved on lateral view; coxites slightly sclerotized, with short setae; baculi subparallel; styli well- developed, directed backwards. Spermatheca (Fig. 3E) about ⅛ as long as ventrites 1-5, somewhat subglobose, with short collum, well- developed ramus and long cornu; spermathecal gland 1.5× as long as spermatheca; spermathecal duct fine, moderately sclerotized, very long (almost twice as long as ovipositor, about 10× as long as spermatheca).

Male genitalia: Penis as long as ventrites 1-5; tube with rounded apex (Fig. 3F), slightly longer than apodemes, fairly curved in lateral view (Fig. 3G), subterminal narrow ostium; endophallus with pair of sclerotized elongate sclerites, and long, curled flagellum (Fig. 3G).

Etymology: The species is named in honor of Dr. Cleide Costa, the outstanding Brazilian Coleoptera specialist.

Geographic distribution:Stenocyphus costae sp. nov., is known only for Espírito Santo and Minas Gerais states in Brazil. It is distributed on hilly areas of central-eastern Espírito Santo state, Santa Teresa, and the Serra do Caraça in Minas Gerais, which are protected areas of Atlantic forest.

Remarks:Stenocyphus costae sp. nov., is the sister species of the remaining three species of Stenocyphus.

Key to species of Stenocyphus Marshall

1. Scaly vestiture iridescent green; scape reaching half of eyes; elytral tubercles covered with brown, stiff, long scale-like setae (Fig. 2) Stenocyphus costae sp. nov.

1’. Scaly vestiture cream or tan, and opaque; scape exceeding posterior margin of eyes; elytral tubercles not covered with brown, stiff, long scale-like setae 2

2. Elytral disc with one pair of large conical tubercles, slightly directed backwards, on posterior two thirds of interval 5, near declivity; scutellum suboval; protibiae without mucro and denticles; ovipositor with coarse setae along external sides of apical ⅔ of baculi (see del Río & Lanteri, 2013del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43., figs. 1, 4) S. bituberosus

2’. Elytral disc with more than one pair of tubercles; scutellum subtriangular; protibiae with mucro and denticles; ovipositor without coarse setae along sides of baculi 3

3. Elytral disc with three pairs of tubercles, two on interval 3 and one on interval 5; the largest pair of tubercles slightly directed backwards, placed on posterior ⅔ of interval 3, and followed by a small one; tubercle on interval 5, large but rounded and placed near declivity; penis flattenned towards apex in lateral view (see del Río & Lanteri, 2013del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43., figs. 2, 5) S. sextuberosus

3’. Elytral disc with three series of conical tubercles along intervals 3, 5 and 7, from base to apex, with the largest tubercles placed near declivity of interval 3; penis not flattened towards apex in lateral view (see del Río & Lanteri, 2013del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43., figs. 3, 6) S. tuberculatus

DISCUSSION

The new species is very similar in appearance to that of the genus Hadropus, but besides this superficial similarity it is not related to this genus (see results of the cladistic analysis). In the single species of Hadropus the rostrum is much shorter and wider, and lacks lateral carina; the epistome is more differentiated from the post-rostrum; the spermatheca has a particular shape (without collum, with broad and prominent ramus); and the penis lacks flagellum. All these characters are important to separate genera in the tribe Naupactini.

On the contrary, Stenocyphus costae sp. nov., shares most synapomorphies of Stenocyphus (see results of the cladistic analysis) and has a particular combination of features that allow distinction from the other species of this genus: e.g., scape not reaching hind margin of eye (char. 31.0); club oval, very short (length/width 2.0 to 2.25×) (char. 37.0); pronotum convex (char. 44.1), with postero-lateral angles projected (char. 45.1); procoxae twice as close to anterior margin than to posterior margin of prosternum (char. 65.2); and apodeme of sternite VIII less than 2× as long as plate (char. 80.0).

With the inclusion of the new species in Stenocyphus the distribution of this genus extends western to the state of Minas Gerais. Consequently, this genus does not occur only in the Atlantic Forest (oriental slopes of the coastal hills of Brazil, characterized by a pluvial forest of trees of 30-40 meters, with a lower stratum rich in palms, lianas and epiphytes), but also in the transition area with the Cerrado (largest savanna forest, with open forest having low trees, shrubs, a stratum of herbs rich in Poaceae and Fabaceae). The Serra de Caraça (Minas Gerais), where the species S. costae sp. nov., coexists with Hadropus albiceris, is a unique area of great biological diversity, as it covers a variety of habitats, including montane forest, cloud forest, shrubby montane savannas and high-altitude grasslands. It contains species endemic to the Cerrado (particularly those restricted to campos rupestres in the Espinhaço mountain range), as well as Atlantic Forest endemics. This is an area of high conservation priority in Minas Gerais, where the flora and fauna are currently threatened of extinction (Costa et al., 1998Costa, C.M.R.; Herrmann, G.; Martins, C.S.; Lins, L.V. & Lamas, I.R. 1998. Biodiversidade em Minas Gerais: um atlas para sua conservação. Belo Horizonte, Fundação Biodiversitas.).

It would be very important to collect more extensively in this area of Brazil to find out the accurate distribution of Stenocyphus and its possible intraspecific variation.

ACKNOWLEDGMENTS

We thank all the specialists and curators that loaned us specimens for study, and/or facilitate the examination of the material; to Lic. Emilia P. Hernández (CIC, “Comisión de Investigaciones Científicas de la Provincia de Buenos Aires”) for the technical support. This work was supported by the National Agency of Promotion of Science of Argentina (ANPCyT, grants BID-PICT 2016-2798 and 2016-0739) and by the National University of La Plata (UNLP, grant 11/N852). This paper is dedicated in honor to Dr. Cleide Costa, in recognition of her contributions to the knowledge of Neotropical beetles.

REFERENCES

  • Costa, C.M.R.; Herrmann, G.; Martins, C.S.; Lins, L.V. & Lamas, I.R. 1998. Biodiversidade em Minas Gerais: um atlas para sua conservação. Belo Horizonte, Fundação Biodiversitas.
  • del Río, M.G. & Lanteri, A.A. 2011. Taxonomic revision of the genus Hadropus Schoenherr (Coleoptera: Curculionidae) with comments on infraspecific variation. Transactions of the American Entomological Society, 137(344): 307-315.
  • del Río, M.G. & Lanteri, A.A. 2013. Taxonomic revision of the genus Stenocyphus Marshall (Coleoptera: Curculionidae) from Brazil. ZooKeys, 357: 29-43.
  • Farris, J.S. 1989. The retention index and the rescaled consistency index. Cladistics, 5: 417-419.
  • Felseinstein, J. 1985. Confidence limits on phylogenies: an approach using the Bootstrap. Evolution, 39: 783-791.
  • Goloboff, P.A. & Catalano, S. 2016. TNT version 1.5, including a full implementation of phylogenetic morphometrics. Cladistics, 32(3): 221-238.
  • Goloboff, P.A. & Farris, J.S. 2001. Methods for quick consensus estimation. Cladistics, 17: 26-34.
  • Kluge, A.G. & Farris, J.S. 1969. Quantitative phyletics and the evolution of anurans. Systematic Zoology, 18: 1-32.
  • Lanteri, A.A. & del Río, M.G. 2017. Phylogeny of the tribe Naupactini (Coleoptera: Curculionidae) based on morphological characters. Systematic Entomology, 42(2): 429-447.
  • Maddison, W.P. 1993. Missing data versus missing characters in phylogenetic analysis. Systematic Biology, 42: 576-581.

ADDITIONAL SUPPORTING INFORMATION

Table S1
List of morphological characters and character states used for the phylogenetic analysis. The list and the figures called there are from Lanteri & del Río (2017Lanteri, A.A. & del Río, M.G. 2017. Phylogeny of the tribe Naupactini (Coleoptera: Curculionidae) based on morphological characters. Systematic Entomology, 42(2): 429-447.).

Table S2
Data matrix with 76 terminal taxa (72 for the ingroup plus four outgroups) and 100 morphological characters, modified from that of Lanteri & del Río 2017, with the inclusion of the species Stenocyphus costae sp. nov.

Edited by

Edited by: Sônia A. Casari / Gabriel Biffi

Publication Dates

  • Publication in this collection
    13 July 2020
  • Date of issue
    2020

History

  • Received
    08 Nov 2019
  • Accepted
    21 Jan 2020
  • Published
    04 Mar 2020
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