Gnathymenus spinifer, Assing, 2017

Assing, Volker, 2017, Two new species of Gnathymenus from Ecuador (Coleoptera: Staphylinidae: Paederinae: Dolicaonina), Linzer biologische Beiträge 49 (2), pp. 1023-1028 : 1025-1028

Gnathymenus spinifer nov.sp. ( Figs 10-17 )

T y p e m a t e r i a l: Holotype 3: " ECUADOR - Pastaza, Paya near S. Clara, 950 m, canopy fogging, 30.VII.-1.VIII.2010, leg. Rossi, Bernardi, Torres / Holotypus 3 Gnathymenus spinifer sp. n. det. V. Assing 2017" (cAss). Paratypes 3: same data as holotype (cAss).

E t y m o l o g y: The specific epithet (Latin, adjective: carrying a spine) alludes to the conspicuous subapical spine of the aedeagus.

D e s c r i p t i o n: Very small species; body length 2.6-3.0 mm; length of forebody 1.4-1.5 mm. Coloration: head reddish to reddish-brown; pronotum pale-reddish to reddish; elytra dark-brown to blackish-brown; abdomen bicoloured with segments III-VI reddish and the posterior segments brown to dark-brown; legs, antennae, and maxillary palpi yellowish.

Head ( Fig. 10 ) weakly transverse, approximately 1.08 times as broad as long, lateral margins behind eyes converging in dorsal view; posterior angles moderately marked; punctation of dorsal surface sparse, near dorsal margin of eyes with a cluster of coarser and denser punctures on either side; interstices without microsculpture. Eyes longer than postocular region in dorsal view. Antenna ( Fig. 1 ) approximately 0.6 mm long and with elongate antennomere XI.

Pronotum ( Fig. 10 ) approximately 1.12 times as long as broad and as broad as head, distinctly tapering posteriad; midline broadly impunctate, laterally delimited by a somewhat irregular dorsal series of punctures on either side; punctation moderately fine and moderately sparse; interstices without microsculpture.

Elytra ( Fig. 10 ) approximately as long as pronotum, or nearly so, and with marked humeral angles; punctation sparse, fine and shallow; interstices without microsculpture. Hind wings present. Legs short and with short tarsi; metatarsomere I longer than II, but shorter than the combined length of metatarsomeres II and III.

Abdomen narrower than elytra; segments III-VI with distinct paratergites; punctation finer and sparser on posterior than on anterior tergites; interstices with distinct transverse microsculpture; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII strongly convex.

3: sternite VII ( Fig. 11 ) with rather sparse unmodified pubescence, posterior margin broadly concave; sternite VIII ( Fig. 12 ) approximately as long as broad and with deep and narrow posterior incision; aedeagus ( Figs 13-17 ) 0.43 mm long, very slender, somewhat asymmetric, and subapically with a prominent sclerotized spine; parameres completely reduced.

C o m p a r a t i v e n o t e s: This species is characterized by its small size, rather long elytra, an elongate antennomere XI, large eyes, its coloration, a weakly modified male sternite VII, and particularly by the conspicuous morphology of the aedeagus. Regarding its male sexual characters it is somewhat similar to G. angulus HERMAN, 1981 ( Ecuador: Napo), which differs by larger body size, coloration (particularly of the abdomen), a posteriorly less concave male sternite VIII, and by the less intricate structure of the aedeagus. For illustrations of G. angulus 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. arboreus .

Figures

Figs 10-17: Gnathymenus spinifer nov.sp.: (10) forebody; (11) male sternite VII; (12) male sternite VIII; (13-16) aedeagus in lateral and in ventral view; (17) subapical spine of aedeagus in lateral view. Scale bars: 10: 1.0 mm; 11-17: 0.1 mm.

Figs 1-9: Gnathymenus arboreus nov.sp.: (1) forebody; (2) male sternite VII; (3) male sternite VIII; (4-9) aedeagus in ventral and in lateral view. Scale bars: 1: 1.0 mm; 2-3: 0.2 mm; 4-9: 0.1 mm.