A new species of Chalepides Casey, 1915 (Scarabaeidae, Dynastinae, Cyclocephalini) from the Pantanal of Brazil

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.


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) 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. 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).

Results and discussion
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).
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).
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.
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.