Tropimenelytron alishanum, Assing, 2011

Assing, V., 2011, A new micropterous and microphthalmous species of Tropimenelytron from Taiwan (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 43 (1), pp. 271-274 : 272-274

Tropimenelytron alishanum nov.sp. ( Figs 1-9 )

T y p e m a t e r i a l: Holotype: " Taiwan - Chiayi Co., Alishan, Road 18 to Youth Activ. Centre, 2000 m, tree base hollow, 7.I.2009, leg. Vít [3] / Holotypus Tropimenelytron alishanum sp. n., det. V. Assing 2009" (cAss). Paratype: same data as holotype (MHNG).

D e s c r i p t i o n: Body length 3.5-4.2 mm; habitus as in Fig. 1 . Coloration: body uniformly reddish to dark-reddish; legs reddish-yellow.

Head oblong, 1.06-1.12 times as long as wide ( Fig. 2 ); dorsal surface with relatively sparse, extremely fine, barely noticeable punctation and with distinct microreticulation; genal carinae fine posteriorly and obsolete anteriorly. Eyes reduced, not protruding from lateral contours of head in dorsal view, of oblong oval shape, approximately 1/3 the length of postocular region in lateral view, and without distinct ommatidia and pigmentation ( Fig. 3 ). Antenna with antennomeres II and III elongate and of subequal length; IV-X of increasing width and increasingly transverse; VIII-X slightly less than twice as wide as long ( Fig. 4 ).

Pronotum with sexual dimorphism; punctation and microsculpture similar to those of head ( Fig. 2 ).

Elytra with sexual dimorphism, short, approximately 0.6 times as long as pronotum ( Fig. 2 ); punctation relatively dense, fine, but clearly more distinct than that of head and pronotum; microsculpture shallow. Hind wings completely reduced.

Abdomen 1.05-1.10 times as wide as elytra, widest at segment VI; tergite III-V with very shallow anterior impressions; tergites VII-VIII with sexual dimorphism; punctation fine and relatively sparse; interstices with fine, but distinct microreticulation; posterior margin of tergite VII without palisade fringe.

: pronotum weakly oblong, 1.03 times as long as wide and 1.25 times as wide as head, posterior margin narrowly concave in the middle; elytra near apex of scutellum with pair of relatively small, subcircular tubercles ( Fig. 2 ); abdominal tergite VII in posterior half with granulose punctation; tergite VIII with granulose punctation (similar to that of posterior half of tergite VII), posterior margin serrate and truncate ( Fig. 5 ); sternite VIII approximately as long as wide, its posterior margin strongly convex ( Fig. 6 ); median lobe of aedeagus as in Figs 7-8 .

: pronotum weakly transverse, 1.05 times as wide as long and 1.30 times as wide as head, posterior margin weakly convex, almost truncate; elytra without tubercles; punctation of abdominal tergites VII-VIII not granulose; posterior margin of tergite VIII weakly convex and not serrate; sternite VIII with weakly convex posterior margin; spermatheca as in Fig. 9.

C o m p a r a t i v e n o t e s: The only previously described microphthalmous and micropterous species of Tropimenelytron known from Taiwan (Kaohsiung Hsien) is T. pacei , from which T. alishanum is readily distinguished by larger size ( T. pacei : 2.7 mm), the modifications of the male pronotum, elytra, and abdominal tergite VII, as well as by the morphology of the aedeagus ( T. pacei : smaller, ventral process narrower in ventral view) and the spermatheca ( T. pacei : distal portion smaller; proximal portion not distinctly S-shaped). For illustrations of the habitus and the genitalia of T. pacei (as Geostibida smetanai) see PACE (1998). From all other Taiwanese representatives of the genus, the new species is readily separated by paler coloration, smaller eyes, and shorter elytra alone. For illustrations of the habitus and the genitalia of recently described species see PACE (2009).

E t y m o l o g y: The specific epithet (adjective) is derived from the name of the mountain range where the type locality is situated.

D i s t r i b u t i o n a n d b i o n o m i c s: The type locality is situated in the Alishan mountain range, Chiayi County, central Taiwan. The type specimens were sifted from a tree base hollow at an altitude of 2000 m.

Figures

Figs 1-9: Tropimenelytron alishanum nov.sp. (1-8: holotype): (1) male habitus; (2) male forebody; (3) head in lateral view; (4) antenna; (5) male tergite VIII; (6) male sternite VIII; (7-8) aedeagus in lateral and in ventral view; (9) spermatheca. Scale bars: 1: 1.0 mm; 2-3: 0.5 mm; 4-6: 0.2 mm; 7-9: 0.1 mm.