Gnathymenus stipulatus, Assing, 2015

Assing, Volker, 2015, New species and additional records of Dolicaonina from Ecuador (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 47 (2), pp. 1119-1132 : 1126-1127

Gnathymenus stipulatus nov.sp. ( Figs 17-24 )

T y p e m a t e r i a l: Holotype 3: " ECUADOR - Zamora Chinchipe, Estacion Cientifica S. Francisco, 3°59'S, 79°05'W, 1900m, 10-14.VIII.2014, Rossi / Holotypus 3 Gnathymenus stipulatus sp. n. det. V. Assing 2014" (cAss).

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun stipula (stubble) and alludes to the modified chaetotaxy of the male sternite VII.

D e s c r i p t i o n: Body length 3.8 mm; length of forebody 2.1 mm. Coloration: body blackish with the pronotum dark-reddish and the abdominal apex (segments VIII-X and posterior margin of segment VII) pale-reddish; legs, antennae, and maxillary palpi yellowish.

Head ( Fig. 17 ) transverse, approximately 1.1 times as broad as long, widest across eyes, and of rectangular shape; posterior angles marked; dorsal surface with some coarse punctures in median dorsal portion and with sparse finer punctures in remainder of dorsal surface; interstices without microsculpture. Eyes rather large and convex, approximately as long as postocular region in dorsal view. Antenna 1.0 mm long.

Pronotum ( Fig. 17 ) 1.15 times as long as broad and 1.1 times as broad as head, widest near anterior angles, and moderately tapering posteriad; midline broadly impunctate, laterally delimited by moderately dense and moderately coarse irregular punctation, not by a distinct dorsal series; interstices without microsculpture.

Elytra ( Fig. 17 ) approximately 0.9 times as long as pronotum and with marked humeral angles; punctation moderately sparse and shallow; interstices without microsculpture. Hind wings probably fully developed. Metatarsomere I aproximately as long as II.

Abdomen slightly narrower than elytra; segments III-VI with distinct paratergites; punctation fine and rather sparse, even finer and sparser on tergites VII-VIII than on anterior tergites; interstices with fine transverse microsculpture; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII obtusely angled in the middle ( Fig. 19 ).

3: sternite IV ( Fig. 18 ) extensively flattened in the middle; sternite V ( Fig. 18 ) with extensive, but shallow median impression, this impression without setae in the middle; sternite VI ( Fig. 18 ) with distinct and moderately deep median impression, this impression without setae in the middle; sternite VII ( Figs 20-21 ) approximately 1.15 times as broad as long and with distinct U-shaped postero-median impression, this impression with approximately 20 strongly modified short and stout black setae, posterior excision one-fourth as deep as length of sternite, margins of this excision with few minute modified setae; sternite VIII ( Fig. 22 ) 1.25 times as long as broad and with conspicuously deep median incision, this incision nearly reaching anterior margin of sternite; aedeagus ( Figs 23-24 ) 0.67 mm long, with ventral process of distinctive shape; parameres completely reduced.

C o m p a r a t i v e n o t e s: The new species differs from all its congeners particularly by the distinctive male sexual characters. Using the key to females in HERMAN (1981), G. stipulatus would key out at couplet 84, together with G. tungus , from which it is distinguished by the completely different male sexual characters, the different coloration ( G. tungus : middle of antennae and penultimate palpomere of maxillary palpus darkened; pronotum pale-reddish; abdominal apex not distinctly paler than remainder of abdomen), the sub-rectangular head with more pronounced posterior angles, the broader and posteriorly less strongly tapering pronotum, the absence of a pair of distinct dorsal series on the pronotum, and the less sparse punctation on the elytra and the abdomen. For illustrations of the male sexual characters of G. tungus see HERMAN (1981).

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The type locality and the circumstances of collection are identical to those of G. crucifer .

Figures

Figs 17-24: Gnathymenus stipulatus nov.sp.: (17) forebody; (18) segments III-VI of male abdomen in ventral view; (19) posterior portion of male tergite VIII; (20) male sternite VII; (21) posteromedian portion of male sternite VII; (22) male sternite VIII; (23-24) aedeagus in lateral and in ventral view. Scale bars: 17-20, 22: 0.5 mm; 21, 23-24: 0.2 mm.