Gnathymenus penicillatus, 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 : 1120-1121

Gnathymenus penicillatus nov.sp. ( Figs 1-9 )

T y p e m a t e r i a l: Holotype 3: " Ecuador Cotopaxi, Volcán Cotopaxi m 3925, 3.VIII.2006, P.M. Giachino / Holotypus 3 Gnathymenus penicillatus sp. n. det. V. Assing 2014" ( SMNS) . Paratypes: 733, 8♀♀: same data as holotype ( SMNS, cAss) ; 2♀♀: " Ecuador Cotopaxi, Volcán Cotopaxi m 4000, 3.VIII.2006, Luca Picciau leg." ( SMNS) .

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun penicillus (brush) and alludes to the pair of tufts of setae on the male sternite VII.

D e s c r i p t i o n: Body length 4.0- 4.6 mm; length of forebody 1.9-2.0 mm. Coloration: head reddish; pronotum reddish-brown to blackish-brown, at least slightly darker than head; elytra blackish; abdomen blackish with the apical segments (VIII-X) palereddish; legs reddish-brown to dark-brown with reddish tarsi; antennae reddish; maxillary palpi reddish with penultimate palpomere infuscate.

Head ( Fig. 1 ) transverse, approximately 1.1 times as broad as long, lateral margins behind eyes subparallel in dorsal view; dorsal surface with sparse and moderately coarse punctation; median dorsal portion impunctate or with few punctures; interstices without microsculpture. Eyes small and weakly convex, approximately half as long as postocular region in dorsal view. Antenna approximately 1.0 mm long.

Pronotum ( Fig. 1 ) approximately 1.15 times as long as broad and slightly broader than head, weakly tapering posteriad; midline broadly impunctate, laterally not delimited by a distinct dorsal series of punctures; punctation of lateral portions similar to that of head; interstices without microsculpture.

Elytra ( Fig. 1 ) short, approximately 0.55 times as long as pronotum and with weakly marked humeral angles; punctation sparse, fine and shallow; interstices without microsculpture. Hind wings completely reduced. Metatarsomere I noticeably longer than II.

Abdomen broader than elytra; segments III-VI with distinct paratergites; punctation moderately sparse, finer on posterior than on anterior tergites; interstices with distinct transverse microsculpture; posterior margin of tergite VII without palisade fringe; posterior margin of tergite VIII obtusely angled in the middle ( Fig. 4 ).

3: sternites III-V unmodified; sternite VI slightly flattened in the middle, otherwise unmodified; sternite VII ( Figs 2-3, 5-6 ) strongly modified, with deep posterior excision, the surroundings of this excision deeply impressed, postero-laterally with two pronounced spine-like processes on either side, margin of posterior excision with a brush-like tuft of long setae on either side; sternite VIII ( Fig. 7 ) oblong, 1.20-1.25 times as long as broad, with conspicuously deep median incision, this incision nearly reaching anterior margin of sternite; aedeagus ( Figs 8-9 ) approximately 0.7 mm long and of distinctive shape; parameres completely reduced.

C o m p a r a t i v e n o t e s: This species is distinguished from all its congeners particularly by the distinctive morphology of the aedeagus and by the distinctive shape and chaetotaxy of the male sternite VII. Based on the similarly modified male sternite VII, G. penicillatus is closely allied to G. praenuptus ROUGEMONT, 2014 from Ecuador (Imbabura), from which it is additionally separated by smaller body size ( G. praenuptus : 6.2 mm). For illustrations of G. praenuptus see ROUGEMONT (2014).

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 is situated in the northeast of Cotopaxi province, Central Ecuador. The type specimens were sifted from litter in the so-called "Paramo formation" at altitudes of 3925 and 4000 m, near the summit of Cotopaxi Volcano (GIACHINO, pers. comm.).

Figures

Figs 1-9: Gnathymenus penicillatus nov.sp.: (1) forebody; (2) segments V-VIII of male abdomen in ventral view; (3) segments V-VIII of male abdomen in lateral view; (4) male tergite VIII; (5) male sternite VII; (6) median portion of male sternite VII; (7) male sternite VIII; (8-9) aedeagus in lateral and in ventral view. Scale bars: 1-5, 7: 0.5 mm; 6, 8-9: 0.2 mm.