Atheta (Microdota) excaecata, Assing, 2009

Assing, V., 2009, New species and additional records of Homalotini, Athetini, Pygostenini, and Lomechusini from Yunnan, China (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 41 (1), pp. 485-507 : 497-498

Atheta (Microdota) excaecata nov.sp. ( Figs 37-41 )

Holotype ♀: China: Yunnan [ CH 07-26], Nujiang Lisu Aut. Pref., Gaoligong Shan, pass 21 km NW Liuku, 3150 m, 25°58'22"N, 98°41'00"E, bamboo with shrubs, litter sifted, 9. VI.2007, M. Schülke / Holotypus ♀ Atheta excaecata sp.n. det. V. Assing 2007 (cAss).

D e s c r i p t i o n: 2.6 mm. Habitus as in Fig. 37 . Coloration of whole body uniformly yellowish to yellowish-brown.

Head slightly wedge-shaped, approximately as wide as long ( Fig. 38 ); punctation rather sparse and extremely fine, barely noticeable; surface with distinct microreticulation and with moderate shine. Eyes strongly reduced ( Fig. 39 ), composed of only approximately 4 ommatidia, not projecting from lateral contours of head, approximately 1/6 the length of postocular region in dorsal view. Antennae gradually and distinctly incrassate apically, antennomere X approximately twice as wide as long ( Fig. 40 ).

Pronotum slender, approximately 1.10 times as wide as long and 1.15 times as wide as head; maximal width in anterior half; posterior angles weakly marked, rounded ( Fig. 38 ); punctation and microsculpture slightly more distinct than those of head; pubescence of midline unclear (somewhat disturbed in holotype).

Elytra reduced, slightly narrower than and at suture approximately 0.5 times as long as pronotum ( Fig. 38 ); punctation sparse and very fine, slightly more distinct than that of pronotum; microsculpture absent, interstices shiny. Hind wings completely reduced. Metatarsomere I short, approximately as long as II.

Abdomen conspicuously large in relation to forebody ( Fig. 37 ), approximately 1.4 times as wide as elytra, widest at segment V; tergites III-V anteriorly with shallow impression; punctation very fine, moderately sparse on tergite III, decreasing in density from tergites IV-VI, and extremely sparse on tergites VI-VIII; microsculpture very shallow on anterior tergites, distinct on posterior tergites; posterior margin of tergite VII without palisade fringe; tergite VIII apparently with sexual dimorphism.

Ƌ: unknown.

♀: posterior margin of tergite VIII in the middle broadly and shallowly concave ; sternite VIII slightly longer than tergite VIII, its posterior margin strongly convex, not concave in the middle; spermatheca of highly distinctive morphology ( Fig. 41 ).

E t y m o l o g y: The name (Latin, adjective: blinded) refers to the strongly reduced eyes.

C o m p a r a t i v e n o t e s: From all its congeners known from China, this remarkable species is readily distinguished by numerous characters: the uniformly pale coloration, the strongly reduced eyes, the extremely short and narrow elytra, as well as the distinctive female primary and secondary sexual characters.

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 Gaoligong Shan, to the northwest of Liuku in western Yunnan province. As can be inferred from the adaptive reductions of pigmentation, eye size, and wings, as well as from the altitude (3150 m) of the type locality, the distribution of the species is probably restricted. The holotype was sifted from litter beneath bamboo and shrubs.

Figures

Figs 37-41: Atheta excaecata nov.sp.: (37) habitus; (38) forebody; (39) head in lateral view; (40) antenna; (41) spermatheca. Scale bars: 37: 1.0 mm; 38-40: 0.2 mm; 41: 0.1 mm.