Drusilla penicillata, 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 : 59-60

Drusilla penicillata spec. nov.

urn:lsid:zoobank.org:act:CAA17FAD-AE2A-496C-9D08-84D34358BDD5

( Figs 48–52 , 140–144)

Type material: Holotype: “ PHILIPPINES: Mindanao , Barangay Baganihan, Marilog D., Epol Falls, 7°27'N, 125°14'E, wet litter and debris near waterfall sift., 27.III.2018, leg. Shavrin / Holotypus Drusilla penicillata sp. n., det. V. Assing 2018” (cAss). Paratypes: 1, 1: same data as holotype; 1: “ PHILIPPINES: Mindanao , Barangay Baganihan, Marilog D., Eagles Ridge, 7°45'N, 125°23'E, secondary forest, wet litter sifted, 26–28.III.2018, leg. Shavrin ” (cAss) .

Etymology: The specific epithet is an adjective derived from the Latin noun penicillus (brush) and alludes to the presence of a setiferous tubercle on the male head.

Description: Relatively large species: body length 5.8–6.7 mm; length of forebody 2.8–3.0 mm. Habitus as in Fig. 48 . Coloration: body pale-reddish with the posterior portions of paratergites III–VI weakly infuscate; legs with the tarsi reddish, the bases of the meso- and metafemora and all of the meso- and metatibiae yellow, and the femora (except for the bases of the meso- and metafemora) and the protibae pale-brown; antennae and maxillary palpi pale-reddish.

Head ( Fig. 49 ) sexually dimorphic, transverse, 1.05– 1.10 times as broad as long; punctation very fine and moderately sparse, punctures bearing long sub-erect to depressed setae directed mediad; median dorsal portion extensively impunctate; interstices without microreticulation. Eyes moderately large, approximately 1.5 times as long as distance from posterior margin of eye to posterior constriction in dorsal view. Antenna ( Fig. 51 ) 2.9 mm long and slender; antennomeres IV–X oblong, IV twice as long as broad, V–X decreasingly oblong, X weakly oblong, and XI shorter than the combined length of IX and X.

Pronotum ( Fig. 49 ) without sexual dimorphism, strongly convex in cross-section, approximately as broad as long and slightly broader than head, broadest at anterior angles; along midline with sharp and narrow sulcus posteriorly terminating in a deep impression; lateral margins indistinctly sinuate in dorsal view; posterior angles obtusely marked; punctation dense and distinct; with several long black setae in lateral portions; interstices without microsculpture.

Elytra ( Fig. 49 ) approximately 0.8 times as long as pronotum, strongly transverse (width combined); punctation very dense, coarse, and somewhat asperate, denser near scutellum than elsewhere; interstices reduced to narrow ridges, without microsculpture. Hind wings fully developed. Legs very long and slender; metatarsomere I longer than the combined length of III and IV.

Abdomen ( Fig. 52 ) approximately as broad as elytra; tergite III with moderately dense and distinct setiferous punctation; tergite IV with a variable number of setiferous setae at posterior margin and with a transverse row of setiferous setae across middle; tergites V–VII with setiferous punctures at posterior margins and with very sparse punctation elsewhere; tergites III–VI with shallow and very fine transverse microsculpture visible only at high magnification; tergites VII–VIII with shallow microsculpture composed of transverse meshes; posterior margin of tergite VII with palisade fringe.

: head ( Fig. 50 ) in the middle of dorsal surface with small tubercle bearing approximately 4–5 long pale setae; tergite VIII (Fig. 140) with posterior margin weakly concave in the middle, in anterior portion with numerous gland openings; sternite VIII much longer than tergite VIII, with convex posterior margin, in anterior portion with numerous gland openings; median lobe of aedeagus approximately 0.9 mm long and shaped as in Figs 141–142; ventral process apically abruptly narrowed in ventral view; parameres approximately 0.8 mm long.

: tergite VIII (Fig. 143) with moderately sparse gland openings anteriorly, posterior margin very weakly concave in the middle, nearly truncate; sternite VIII with moderately sparse gland openings anteriorly, posterior margin broadly convex, in the middle with short modified marginal setae; spermatheca as in Fig. 144.

Comparative notes: As can be inferred from the similar general morphology of the genitalia, D. penicillata belongs to the same species group as D. shavrini . It is distinguished from all other species previously recorded from the Philippines (see the comparative notes in the section on D. shavrini ) and the new species described in the present paper by the coloration and larger body size alone. In addition, it is characterized by the brush-like tubercle on the male head and by the shapes of the median lobe of the aedeagus and of the spermatheca. Regarding the coloration and the general morphology of the genitalia, D. penicillata somewhat resembles D. perforans from Vietnam, from which it differs by larger body size, the coloration of the antennae, legs, elytra, and abdomen ( D. perforans : antennomeres III–X infuscate; legs yellow with the apices of the metafemora infuscate; elytra infuscate in postero-lateral portions; abdomen yellow with the posterior portions of paratergites III–VI, the posterior portion of tergite V, most of tergite VI, and the median portion of tergite VII blackish), by the modifications of the male head, by a larger and less slender pronotum without a broad median impression, with weakly sinuate lateral margins, and with much finer and non-granulose punctation, and by the genitalia.

Distribution and natural history: The type specimens were collected in two geographically close localities in the Central Mindanao, Philippines, by sifting wet litter near a waterfall and in a a secondary broad-leaved forest.

Figures

Figs 35–52: Drusilla bispinosa (35–43), D. shavrini (44–47), and D. penicillata (48–52): male forebody (35, 45, 49); antenna (36, 46, 51); male abdomen (37, 47, 52); anterior portion of male abdomen (38–39); posterior portion of male abdomen in dorsal and in lateral view (40–42); posterior portion of female abdomen (43); habitus (44, 48); head in dorso-lateral view (50). Scale bars: 35–49, 51–52: 1.0 mm; 50: 0.5 mm.