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A new species of Chalepides Casey, 1915 (Scarabaeidae, Dynastinae, Cyclocephalini) from the Pantanal of Brazil
expand article infoBrett C. Ratcliffe, Matthias Seidel§
‡ University of Nebraska State Museum, Lincoln, United States of America
§ Universität Hamburg – Zoological Museum, Hamburg, Germany
Open Access

Abstract

Chalepides pantanalensis Ratcliffe & Seidel is described as a new species from the Pantanal region in Brazil. A description, diagnosis for distinguishing the species, illustrations, and a distribution map are provided. The new species is morphologically compared with C. howdenorum Joly & Escalona and C. osunai Joly & Escalona.

Key Words

Coleoptera, scarab beetle, semi-aquatic, South America, taxonomy

Introduction

The genus Chalepides Casey consists of 14 species distributed in South America with one species in the West Indies (Joly and Escalona 2002; Ratcliffe and Cave 2015). Chalepides species are recognized by a usually prolonged prepygidium with a concomitant shortening of the pygidium; presence of long, dense, tawny setae on the prepygidium that are exposed beyond the elytral apices; antenna with ten antennomeres and the club subequal in length to antennomeres 2–7; clypeus subtrapezoidal; frontoclypeal suture slender, arcuate; pronotum lacking a basal bead; and large claw of the male protarsus entire at its apex, not split.

The new species described here is from the Pantanal region of Brazil, and only Chalepides barbatus argentinus Prell has been reported from this area (Joly and Escalona 2002). Some Chalepides species are closely associated with submerged or partially submerged plants. Even their body shape is similar to that of many aquatic scavenger beetles (Hydrophilidae: Hydrophilinae). The Pantanal region (straddling Brazil’s border with Bolivia and Paraguay) is one of the world’s largest freshwater wetland ecosystem and prime habitat for Chalepides species with semi-aquatic habits. Silvera Guido (1965) suggested that C. barbatus argentinus may attack the water hyacinth, Eichhornia crassipes [Mart.] Solms [Pontederiaceae], in Uruguay. Valla and Cirini (1972) observed a Chalepides species in the water lily, Victoria cruziana D’Orbigny (Nymphaeaceae), in Corrientes Province, Argentina. Endrödi (1973) reported C. luridus (Burmeister) and C. alliaceus (Burmeister) collected on riverbanks. Martínez (1977) collected adults of C. barbatus argentinus Prell and C. luridus in the submerged axillae of Pistia striatiotes Linneaus (Araceae) and other submerged aquatic plants in the provinces of Chaco, Corrientes, Formosa, and Santa Fé in the Argentinian subtropical region.

Materials and methods

For our species delineation, we adhere to the phylogenetic species concept as outlined by Wheeler and Platnick (2000). This concept defines species as the smallest aggregation of populations diagnosable by a unique combination of character states. Not all species are equally diagnosable; some are easily recognized by examining one or a few individuals with a unique set of characters (e.g., the new species described herein).

Specimen label data are quoted verbatim. A forward slash line (/) is used to separate lines on a label, and a double slash line (//) indicates the separation between two labels.

Results and discussion

Superfamily Scarabaeoidea Latreille, 1802

Family Scarabaeidae Latreille, 1802

Subfamily Dynastinae MacLeay, 1819

Tribe Cyclocephalini Laporte, 1840

Genus Chalepides Casey, 1915

Chalepides pantanalensis Ratcliffe & Seidel, sp. nov.

Figs 1, 2, 4, 5

Type material

Holotype male labeled “BRAZIL/ Pantanal-Fazenda/ Natureza 4.-8.11.2005/ lgt. Z. Tüdös” and with our red holotype label. Allotype female labeled “Brazil, Pantanal/ Fazenda 4 cantos, 7.-10.5.2012/ 18°36'54.40"S, 56°15'56.97"W/ lgt. O. Konvicka” and with our red allotype label. One male and three female paratypes with same data as holotype and each with our yellow paratype label. Two male paratypes with same data as allotype and each with our yellow paratype label. Holotype deposited at the Zoological Museum (ZMH), Centrum für Naturkunde, Universität Hamburg, Hamburg, Germany. Allotype and one male paratype deposited at the University of Nebraska State Museum (UNSM), Lincoln, NE, USA; one male paratype deposited in the Matthias Seidel Collection (MSPC), Hamburg, Germany; and one male and three female paratypes deposited in the Ondřej Konvička Collection, Zlín, Czechia (OKPC).

Figure 1.

Holotype, dorsal view, of Chalepides pantanalensis Ratcliffe & Seidel, sp. nov.

Diagnosis

Chalepides pantanalensis will key to couplet 11 in Endrödi (1985) which ends with C. comes Prell (Venezuela, Colombia, Brazil) where the character states do not match: degree of punctation of pronotum versus frons, pygidial sculpturing, and form of the parameres. In Joly and Escalona (2002), it will key to couplet 8 for C. osunai Joly & Escalona (Venezuela) and C. howdenorum Joly & Escalona (northern Bolivia), the only Chalepides species with a bulbous and rounded apex of the parameres (as in C. pantanalensis). Chalepides pantanalensis has some character states seen in both of these species. The parameres are nearly identical to those of C. howdenorum, but the male of C. pantanalensis has a tooth on the venter of protarsomere 5 (absent in C. howdenorum, Fig. 3) and the larger protarsal claw is short and thick in C. pantanalensis (narrowly elongate in C. howdenorum) (compare Figs 2 and 3).

Figures 2, 3.

Male protarsal large claw of (2) C. pantanalensis Ratcliffe & Seidel, sp. nov. and (3) C. howdenorum Joly & Escalona.

The male of C. pantanalensis shares with C. osunai a tooth on the venter of protarsomere 5 and a larger short, thick protarsal claw, but C. pantanalensis has a greenish sheen (absent in C. osunai), a densely punctate clypeus (sparsely punctate in C. osunai), and shorter, suboval parameres (elongate in C. osunai).

Description of holotype

(Fig. 1). Male. Length 16.7 mm; width 6.9 mm. Color black with faint olive-green sheen. Head: Frons with small, moderately dense, ocellate punctures. Clypeus with small, dense, ocellate punctures; apex broadly, shallowly emarginate, slightly reflexed. Frontal suture arcuate, complete. Interocular width equals 6.0 transverse eye diameters. Pronotum: Surface with small, sparse, ocellate punctures. Elytra: Surface punctate-striate; punctures small, ocellate, separated by about 1 puncture diameter in each row, moderately dense in intervals. Sutural stria a row of small punctures. Pygidium: Prepygidium elongated, coarsely and longitudinally strigose, with long, dense, tawny setae. Pygidium short; surface shiny with large, dense, setigerous punctures, punctures becoming small in lateral angles; setae short, moderately dense, tawny. Surface convex in lateral view. Legs: Protibia tridentate, teeth subequally spaced. Protarsus enlarged; tarsomere 4 and base of tarsomere 5 densely strigulose ventrally; tarsomere 5 longitudinally carinulate on inner margin and with distinctive tooth beneath (Fig. 2); median claw stout, short, strongly bent (Fig. 2). Metatarsus shorter than metatibia. Venter: Prosternal process long, thick, columnar, apex flattened with raised, round “button” on all but slender, setose posterior margin. Parameres: Each side of shaft at about midpoint with small tooth and then shaft expanded to rounded apex (Fig. 4).

Figure 4.

Parameres, caudal and lateral views, of Chalepides pantanalensis Ratcliffe & Seidel, sp. nov.

Allotype. Female. Length 16.7 mm; width 6.9 mm. As holotype except in the following respects: Legs: Protarsi simple, not enlarged.

Variation

Male (3 paratypes). Length 15.8–16.5 mm; width 6.8–7.3 mm. The paratypes do not differ from the holotype except in size, and the small tooth on the venter of tarsomere 5 is nearly obsolete in one specimen. Female (3 paratypes). Length 15.5–16.5 mm; width 7.0–7.7 mm. The paratypes do not differ from the allotype.

Etymology

The specific epithet is an adjective and refers to the habitat type, the Pantanal, in which this species occurs.

Distribution

Chalepides pantanalensis is known only from Brazil’s Pantanal Region (Fig. 5).

Figure 5.

Location of type localities of Fazenda 4 Cantos and Fazenda Natureza, Mato Grosso do Sul, Brazil

Locality records

8 specimens examined.

Brazil (8) • MATO GROSSO DO SUL (8): Fazenda 4 Cantos, Fazenda Natureza (140 km NW Campo Grande).

Temporal distribution

May (3), November (5).

Natural history

Nothing is known of the life history of C. pantanalensis other than the specimens were presumably collected at lights as are other species of Chalepides.

Acknowledgments

We thank Ondřej Konvička (Zlín, Czechia) for making the specimens available for study, Paschoal Grossi (Universidade Federal Rural de Pernambuco, Recife, Brazil) for initial remarks on the species, and two anonymous reviewers who provided valuable suggestions to improve the manuscript. We are grateful for the publication support of the Centrum für Naturkunde (CeNak) – Center of Natural History – University of Hamburg.

References

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