Atalantycha, Kazantsev, 2005

Kazantsev, Sergey, 2005, A Review of Ancistronycha Märkel with the Description of Atalantycha, a New Nearctic Genus (Coleoptera: Cantharidae), The Coleopterists Bulletin 59 (2), pp. 204-210 : 207-208

Atalantycha , new genus

Type species. Telephorus dentiger Leconte, 1851 .

Description. Head coarsely and densely punctured behind eyes, with oblique impressions behind antennal insertions. Mandibles simple, externally straight in the middle third. Distal maxillary palpomere relatively small, widest near the middle. Clypeus semi-triangular, with anterior margin rounded, with weak median emargination. Antennae long, filiform, with antennomere 2 about twice as short as antennomere 3, median antennomeres without glabrous grooves. Primary antennal pubescence short and decumbent, with more elongate robust hairs, more abundant on apex of each antennomere.

Pronotum transverse, slightly constricted anteriorly, anterior angles rounded and posterior angles pronounced, anterior and lateral margins deflexed. Scutellum widely triangular, with posterior margin finely punctured and rounded.Elytra coarsely rugose-punctate, with no traces of longitudinal costae. Elytral pubescence simple, short and decumbent. Female caudal abdominal ventrite trapezoidal, with conspicuous median emargination apically ( Fig. 7 ). Legs long and slender, all tarsomeres bearing plantar pads; metatibial spurs similar; all claws in both sexes with conspicuous tooth ( Fig. 8 ) (except in A. bilineata wherein only anterior claw of each tarsi toothed at base). Aedeagus dorso-ventrally flattened, with dorsal plate greatly reduced, median lobe dorso-ventrally flattened, laterophyses reduced and parameres internally hooked and apically bifid ( Figs. 9–11 ).

Comments. McKey-Fender (1950) transferred three species of Nearctic Cantharini from Cantharis Linnaeus, 1758 , to Ancistronycha , considered by her as a subgenus of Cantharis , on the basis of alleged similarity of the male genitalia and the tarsal claws. Oddly, these very characters, at least at the current level of knowledge of the family, place these species and Ancistronycha in completely different groups of genera. This has necessitated the erection of Atalantycha , new genus, to accommodate these species.

The structure of the pronotum and claws in Atalantycha resembles those of Rhaxonycha Motschulsky, 1860 , but these genera must be differentiated by the very different structures of their aedeagi. Characters separating the new genus from the remainder of the genera of Cantharini are more obvious and include the conspicuously toothed claws in both sexes, the rounded anterior and pronounced posterior angles of the pronotum, the shape of the caudal abdominal ventrite in female, the aedeagus with a reduced dorsal plate and laterophyses, the bifid apex of the parameres, etc. The structure of the aedeagus suggests that a possible close relationship exists between Atalantycha and Cantharis . The type species of the latter, C. fusca Linnaeus, 1758 , has 208 similar male genitalia—but very differently shaped pronotum and dissimilar structure of the claws. Therefore, expansion of the definition of any existing genus of Cantharini to accommodate the species placed in Atalantycha without compromising its monophyly is not possible.

Atalantycha , as ‘‘ Ancistronycha ,’’ may be differentiated from all other genera of Nearctic Cantharini using the key provided by Ramsdale (2002), except for Pacificanthia Kazantsev , which was described subsequently ( Kazantsev 2001). Atalantycha may be easily distinguished from Pacificanthia by the different structure of the pronotum, tibiae, claws and aedeagus.

The generic name is derived from Atlantic, as all species of the new genus occur in eastern, mostly Atlantic, states/provinces of the USA and Canada. Gender feminine.

Atalantycha contains the following taxa:

Figures

Figs. 7–11. Protarsal claw, caudal abdominal ventrite and aedeagi of Atalantycha. 7–9) A. dentigera (Leconte); 7) female, caudal abdominal ventrite; 8) male, protarsal claw; 9) male, aedeagus, dorsal view; 10) A. neglecta (Fall), aedeagus, dorsal view; 11) A. bilineata (Say), aedeagus, dorsal view. Scale: 0.5 mm.