Drusilla (Drusilla) palata, Assing, 2015

Assing, Volker, 2015, New species and additional records of Lomechusini from the Palaearctic region, primarily from China (Coleoptera: Staphylinidae: Aleocharinae), Beiträge Zur Entomologie = Contributions to Entomology 65 (2), pp. 243-262 : 251-252

Drusilla (Drusilla) palata spec. nov.

( Figs 26–33 )

Type material: Holotype ♂: “ CHINA (Yunnan) Dali Bai Aut. Pref. , Wuliang Shan , 20 km NW Weishan 1900 m (creek valley, under bank vegetation, stones, gravel) 25°19'58"N, 100°07'59"E, 17.IX.2009 D.W. Wrase [58] / Holotypus ♂ Drusilla palata spec. nov. det. V. Assing 2015” ( cAss).

Paratypes: 2 ♂♂: “ CHINA (Yunnan) Dali Bai Aut. Pref., Hóu Hé river bank, 10 km S Weishan, 1650 m (in gravel close to water) 25°08'36.8"N, 100°19'34.5"E, 14.IX.2009 D.W. Wrase [53]” (cSch) .

Etymology: The specific epithet is an adjective derived from the Latin noun pala (shovel) and alludes to the conspicuous shape of the posterior projection of the male sternite VIII.

Description: Body length 5.1–6.3 mm; length of forebody 2.5–2.6 mm. Coloration: head, pronotum, and abdomen blackish; elytra dark-yellowish, with the scutellar region and an extensive lateral spot infuscate; legs uniformly pale-yellowish; antennae blackish-brown; maxillary palpi reddish to dark-brown, with the terminal palpomere yellow.

Head ( Fig. 26 ) approximately 1.2 times as broad as long; dorsal surface with median portion flattened or shallowly impressed; punctation fine to moderately coarse and of variable density, sparse to dense; interstices without microsculpture and glossy. Eyes large and bulging, much longer than distance from posterior margin of eye to posterior constriction of head. Antenna ( Fig. 27 ) 2.1 mm long; antennomeres III–X gradually and very weakly increasing in width; preapical antennomeres weakly transverse.

Pronotum ( Fig. 26 ) 1.06–1.10 times as broad as long and 1.06 times as broad as head, broadest at anterior angles; posterior angles obtusely marked; posteriorly with a very small and indistinct impression; midline with narrow, deep, and sharply delimited furrow extending from posterior impression cephalad, but not reaching anterior margin of pronotum; punctation dense and coarse, not granulose; interstices without microsculpture and glossy. Elytra ( Fig. 26 ) approximately 0.9 times as long as pronotum; humeral angles marked; punctation dense, similar to that of pronotum. Hind wings fully developed. Metatarsomere I shorter than the combined length of II–IV.

Abdomen ( Fig. 28 ) narrower than elytra; tergites III– VII without sexual dimorphism; anterior impressions of tergites III–V and posterior margins of tergites III–VII with fine punctation, remainder of tergal surfaces with very sparse punctation; posterior margin of tergite VII with palisade fringe.

♂: pronotum ( Fig. 26 ) with extensive and pronounced median impression in posterior half; tergite VIII ( Fig. 29 ) strongly transverse and with pronounced posterior concavity of nearly semi-circular shape; sternite VIII ( Fig. 30 ) of highly distinctive shape, posteriorly with a pronounced truncate projection and with acutely projecting posterior angles; median lobe of aedeagus ( Figs 31–32 ) 0.9 mm long and of weakly derived morphology, with pronounced crista apicalis, and with short flagellum and additional dark structures in internal sac; paramere ( Fig. 33 ) approximately 0.75 mm long, only slightly shorter than median lobe.

♀: unknown.

Comparative notes: From the externally (size, coloration, proportions, punctation) similar and syntopic D. flagellata , this species is readily distinguished by the uniformly yellowish legs, the deeper impression on the male pronotum, the slightly different coloration of the elytra, the absence of a sexual dimorphism of the elytra, the competely different shapes of the male tergite and sternite VIII, the completely different morphology of the median lobe of the aedeagus, and the distinctly larger and differently shaped paramere.

Distribution and natural history: Drusilla palata is known from two localities in West Yunnan. The specimens were collected from gravel on the banks of a stream and a river at altitudes of 1650 and 1900 m, in one locality together with D. flagellata .

Figures

Figs 26–33:Drusillapalataspec. nov.:maleforebody (26);antenna (27);maleabdomen (28);maletergiteVIII (29);malesternite VIII (30); median lobe of aedeagus in lateral and in ventral view (31–32); paramere (33). Scale bars:26–28:1.0 mm; 29–33: 0.5 mm.