Drusilla breviuter, Assing, 2019

Assing, Volker, 2019, On the Lomechusini fauna of the Palaearctic and Oriental regions. XXVI. New species, a new synonymy, and additional records (Coleoptera: Staphylinidae: Aleocharinae), Beiträge Zur Entomologie = Contributions to Entomology 69 (1), pp. 33-70 : 61-62

Drusilla breviuter spec. nov.

urn:lsid:zoobank.org:act:43EDA558-1DBF-4861-B73F-F292EF6169C5

(Figs 59–63, 148–152)

Type material: Holotype: “ PHILIPPINES: Mindanao, Davao, Boss Carreon Function Hall , 7°17'N, 125°41'E, slope near river, litter sifted, 28.III.2018, leg. Shavrin / Holotypus Drusilla breviuter sp. n., det. V. Assing 2018” (cAss) . Paratypes: 1 [teneral], 1: same data as holotype (cAss).

Etymology: The specific epithet is a noun in apposition composed of the Latin adjective brevis (short) and the Latin noun uter (hose). It alludes to the small and short spermatheca.

Description: Body length 4.0– 4.7 mm; length of forebody 1.8–2.0 mm. Habitus as in Fig. 59. Coloration: head black; pronotum and elytra black with slight bronze hue; abdomen black with segments III–IV and the narrow posterior margin of tergite V reddish; legs uniformly yellow; antennae blackish-brown with antennomeres I–II dark-reddish and the apex of antennomere XI reddishyellow; maxillary palpi yellow to pale-reddish with the apical palpomere yellow.

Head (Figs 60–61) transverse, approximately 1.15 times as broad as long, without sexual dimorphism; punctation very fine and moderately dense; interstices without microreticulation. Eyes large and strongly convex, approximately twice as long as distance from posterior margin of eye to posterior constriction in dorsal view. Antenna (Fig. 62) 1.5–1.6 mm long and distinctly incrassate apically; antennomeres IV weakly transverse, V–X of increasing width and increasingly transverse, X approximately 1.5 times as broad as long, and XI slightly longer than the combined length of IX and X.

Pronotum (Figs 60–61) with moderate sexual dimorphism, weakly convex in cross-section, moderately transverse, approximately 1.1 times as broad as long and approximately as broad as head, broadest near anterior angles, moderately tapering posteriad; along midline with very fine sulcus posteriorly terminating in a small impression; lateral margins straight in dorsal view; posterior angles obtusely marked; punctation dense and distinct; interstices without microsculpture.

Elytra (Figs 60–61) approximately 0.85 times as long as pronotum; punctation similar to that of pronotum, but somewhat denser; interstices without microsculpture. Hind wings fully developed. Metatarsomere I relatively short, barely as long as the combined length of III and IV.

Abdomen (Fig. 63) broad and relatively short, approximately as broad as elytra; tergite III–VII with few punctures at posterior margin, otherwise nearly impunctate; all tergites with shallow and fine transverse microsculpture; posterior margin of tergite VII with palisade fringe.

: pronotum (Fig. 60) with rather extensive, but not very deep median impression, posteriorly with a granulose elevation on either side, punctation slightly granulose; tergite VIII ( Fig. 148 ) strongly transverse, posterior margin with a pronounced tooth on either side, in the middle between these teeth with a broadly truncate projection, in anterior portion with few scattered gland openings; sternite VIII strongly transverse, longer than tergite VIII, with strongly convex posterior margin, in anterior portion without gland openings; median lobe of aedeagus 0.43 mm long and shaped as in Figs 149–150 ; ventral process broad, apically broadly triangular in ventral view.

: pronotum (Fig. 61) only with shallow oblong impression along middle in posterior portion, without elevation, andwithnon-granulosepunctation; tergite VIII ( Fig. 151 ) strongly transverse, posterior margin with broad and shallow excision laterally delimited by a triangular projection on either side, anterior half with scattered gland openings; sternite VIII strongly transverse, posterior margin convex, with long and thin marginal setae in the middle; spermatheca ( Fig. 152 ) comma-shaped, very small and very short.

Comparative notes: Based on the primary sexual characters, D. breviuter is closely allied to D. endopilosella PACE, 2000 from Thailand and D. semimonticola PACE, 2008 (male unknown) from Borneo. It is readily distinguished from both of them by the coloration of the abdomen (completely reddish in the other species) and by the shape of the spermatheca. For illustrations of D. endopilosella and D. semimonticola see PACE (2000, 2008). It differs from the widespread and common D. obliqua (BERNHAUER, 1916) by numerous characters, e.g., a smaller and more slender body with narrower elytra, the coloration of the abdomen and elytra ( D. obliqua : abdomen blackish with the narrow posterior margins of the segments yellow; elytra yellow with the posterolateral portions extensively blackish), much less massive antennae with more transverse antennomeres V–X, the shape of the head (depressed or impressed in D. obliqua ), the modifications of the male pronotum, the shapes of the male and female tergite and sternite VIII, and by the completely different primary sexual characters. For illustrations of D. obliqua see ASSING (2015b, 2017a).

Distribution and natural history: The type locality is situated to the northeast of Davao, near the coast of the Gulf of Davao, Central Mindanao, Philippines. The specimens were sifted from litter on a slope near a river. The male paratype is distinctly teneral.

Figures

Figs 145–165:Drusilla spiniventris(145–147), D. breviuter(148–152), Pheidologitonetes biplicatus (153–154), Zyras conlectus (155– 157), Z. hetzeli (158–159), Z. reductus(160–162), andZ. shavrini(163–165): male tergite VIII (145, 148); median lobe of aedeagus in lateral and in ventral view (146–147, 149–150, 153–156, 158–161, 163–164); female tergite VIII (151); spermatheca (152); paramere (157, 162, 165). Scale bars: 145–151, 153–165: 0.2 mm; 152: 0.1 mm.