Drusilla shavrini, 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 : 57-59

Drusilla shavrini spec. nov.

urn:lsid:zoobank.org:act:7EF756D2-6CFE-4230-AAF4-298C3D1B76BE

( Figs 44–47 , 132–139)

Type material: Holotype: “ PHILIPPINES: Mindanao , Sitio Bitaugan, Kawa-kawa River, 300 m, 6°46'31"N, 126°08'41"E, stream bank, wet litter, debris, dead wood, 24–26.III.2018, leg. Shavrin / Holotypus Drusilla shavrini sp. n., det. V. Assing 2018” (cAss). Paratypes: 4, 6 [partly slightly teneral]: same data as holotype; 2 [1 teneral], 1: “ PHILIPPINES – Mindanao , Mt. Hamiguitan Wildlife Sanctuary, Banakon creek, 6.74°N, 126.15°E, 400 m, wet litter & debris sifted, 22–24. III.2018, leg. Shavrin ” (cAss) .

Etymology: This species is dedicated to Alexey Shavrin

(Daugavpils), the collector of the type series.

Description: Body length 4.3–5.2 mm; length of forebody 2.0– 2.2 mm. Habitus as in Fig. 44 . Coloration: head and pronotum black; elytra dark-yellowish to yellowish-brown with the postero-lateral portion extensively black, sometimes leaving only the sutural and anterior portions paler; abdomen black with the anterior margins of tergites and paratergites III–V yellowish; legs pale-yellow with the profemora, the apical three-fifths of the mesofemora, and the apical half of the metafemora black, protibiae sometimes somewhat infuscate; antennae blackish-brown with the basal two antennomeres slightly paler; maxillary palpi yellow to dark-brown with the apical palpomere yellow.

Head ( Fig. 45 ) transverse, approximately 1.15 times as broad as long; punctation very fine and very sparse; interstices without microreticulation. Eyes large, approximately three times as long as distance from posterior margin of eye to posterior constriction in dorsal view. Antenna ( Fig. 46 ) 1.8–2.0 mm long and rather massive; antennomeres IV weakly oblong, V approximately as long as broad, VI–X weakly transverse, X much less than 1.5 times as broad as long, and XI approximately as long as the combined length of IX and X.

Pronotum ( Fig. 45 ) without sexual dimorphism, strongly convex in cross-section, weakly transverse, 1.03– 1.05 times as broad as long and approximately as broad as head, broadest at anterior angles; along midline with sharp and narrow sulcus posteriorly terminating in a deep impression; lateral margins weakly sinuate in dorsal view; posterior angles obtusely marked; punctation dense and distinct; interstices without microsculpture.

Elytra ( Fig. 45 ) approximately 0.65 times as long as pronotum, strongly transverse (width combined); punctation very dense and rather coarse; interstices reduced to narrow ridges, without microsculpture. Hind wings fully developed. Metatarsomere I approximately as long as the combined length of III and IV.

Abdomen ( Fig. 47 ) narrower than elytra; tergite III with sparse and very fine setiferous punctation; tergites IV–VII with very sparse and extremely fine punctation, median portions of these tergites largely impunctate; tergites III–VI with or without very shallow traces of transverse microsculpture; tergite VII with shallow microsculpture composed of transverse meshes, posterior margin with palisade fringe; tergite VIII with microsculpture composed of transverse meshes.

: tergite VIII (Fig. 132) with broadly and weakly concave, nearly truncate posterior margin, in anterior portion with numerous gland openings; sternite VIII (Fig. 133) much longer than tergite VIII, with convex posterior margin, in anterior portion with numerous gland openings; median lobe of aedeagus approximately 0.8 mm long and shaped as in Figs 134–135; ventral process apically abruptly narrowed in ventral view; parameres approximately 0.7 mm long.

: tergite VIII (Fig. 136) with sparse gland openings anteriorly, posterior margin truncate; sternite VIII (Fig. 137) with sparse gland openings anteriorly, posterior margin broadly convex; spermatheca as in Figs 138–139.

Comparative notes: Eight species of Drusilla were previously known from the Philippines: D. bernhaueri (SCHEERPELTZ, 1934) [replacement name for D. luzonica (BERNHAUER, 1927) ] from Luzon; D. butuanensis (BERN- HAUER, 1916) from Mindanao; D. impressicollis (KRAATZ, 1857) (originally described from Sri Lanka); D. laevicauda (BERNHAUER, 1903) (originally described from Sumatra); D. luzonica (BERNHAUER, 1915) from Luzon; D. philippina (BERNHAUER, 1915) from Luzon; D. plicipennis (BERNHAUER, 1915) from Luzon; D. schawalleri KISTNER, 1994 from Leyte ( HLAVÁČ et al. 2011). Except for D. schawalleri , the primary sexual characters are unknown. Drusilla shavrini is distinguished from all these species as follows:

from D. bernhaueri by the coloration ( D. bernhaueri : body yellow with infuscate head), larger size ( D. bernhaueri : body length slightly more than 3 mm, the shape of the head ( D. bernhaueri : posterior angles acutely produced), much less transverse antennomeres V–X (approximately 1.5 times as broad as long in D. bernhaueri ), the absence of lateral impressions on the pronotum, the punctation of the pronotum and the elytra (granulose in D. bernhaueri ), and the (near) absence of microsculpture on the anterior abdominal tergites;

from D. butuanensis by the coloration ( D. butuanensis : head and pronotum reddish; elytra brownish-yellow with brown lateral and posterior margins; legs pale-yellow), larger body size ( D. butuanensis : 3 mm), extremely fine punctation of the head, less transverse antennomeres V–X, the absence of a deep median impression on the male pronotum, denser punctation of the pronotum and elytra, the absence of a carina in the anterior portion of the male elytra, unmodified male tergites V–VII, and the shape of the posterior margin of tergite VIII ( D. butuanensis : deeply and angularly excised);

from D. impressicollis by the coloration ( D. impressicollis : pronotum brown; legs reddish-yellow), larger size ( D. impressicollis : 3 mm), a broader head in relation to the pronotum ( D. impressicollis : head much narrower than pronotum), the shape of the pronotum ( D. impressicollis : pronotum distinctly transverse), the absence of a sexual dimorphism of the pronotum ( D. impressicollis : male pronotum with broad impression in posterior half and with granulose punctation), and the shape of the posterior margin of the male tergite VIII (denticulate in D. impressicollis );

from D. laevicauda by the coloration ( D. laevicauda : pronotum and elytra brown; paratergites V yellow; legs yellow), larger body size ( D. laevicauda : 3 mm), and the shape of the pronotum (with subparallel lateral margins in D. laevicauda );

from D. luzonica by the coloration ( D. luzonica : antennae reddish; elytra yellowish-brown; legs yellow), the absence of lateral impressions on the pronotum, and shorter elytra;

from D. philippina by the coloration ( D. philippina : antennae reddish; elytra yellowish-brown, in humeral portions extensively yellow) and larger size ( D. philippina : 3 mm); from D. plicipennis by the coloration ( D. plicipennis : head and pronotum reddish; elytra brownish-yellow with brown lateral and posterior margins; legs pale-yellow), larger body size ( D. plicipennis : 3 mm), extremely fine punctation of the head, less transverse antennomeres V–X, the absence of a deep median impression on the male pronotum, the absence of a carina in the anterior portion of the male elytra, unmodified male tergites III– VII, and the shape of the posterior margin of tergite VIII ( D. plicipennis : deeply and angularly excised);

from D. schawalleri by the coloration ( D. schawalleri : legs and antennae uniformly reddish-brown), much more massive antennae ( D. schawalleri : all antennomeres slender and distinctly oblong), and by the completely different primary sexual characters; for illustrations of D. schawalleri see KISTNER (1994).

Several species from other regions have primary sexual characters of a similar type. Drusilla shavrini is distinguished from them as follows:

from D. perforans ASSING, 2015 (North Vietnam) by different coloration, shorter, less slender, and more massive antennae, a transverse pronotum with indistinctly sinuate lateral margins and without a sexual dimorphism, and different sexual characters (for illustrations see ASSING 2015c);

from D. takashii MARUYAMA, 2004 ( Laos) by the coloration ( D. takashii : legs black with the apices of the tibiae and the tarsi reddish-brown), much larger eyes, less slen- der antennae ( D. takashii : all antennomeres oblong), less dense punctation and pubescence of the forebody, and by the primary sexual characters; for illustrations see MARUYAMA (2004);

from D. dimidiata PACE, 1987 (Sulawesi; female unknown) by larger body size ( D. dimidiata : 3.2 mm), the coloration ( D. dimidiata : body brown; antennae dark-reddish with dark-yellowish basal antennomeres; legs yellowish with the apices of the meso- and metafemora slightly infuscate apically), and much larger eyes; for illustrations see PACE (1987);

from D. pervisa PACE, 1987 (Java; male unknown) by the coloration ( D. pervisa : body brown; legs yellow with brownish knees; antennae brown with the basal three antennomeres yellow);

from D. truncatella PACE, 2004 ( Malaysia: Pahang; male unknown) by completely different coloration and by the sexual characters, particularly the shape of the female sternite VIII; for illustrations see PACE (2004);

from D. damingensis PACE, 2012 ( China) by the coloration ( D. damingensis : head and pronotum brown; legs yellowish-red with the apical half or apical third of the femora reddish-brown), much more massive, less slen- der antennae ( D. damingensis : all antennomeres oblong), much larger eyes, the shape of the head (concave in D. damingensis ), the shape of the male tergite III (posterior margin crenulate and concave in D. damingensis ); for illustrations see PACE (2012).

Distribution and natural history: The type specimens were collected in two geographically close localities in the southeast of Mindanao, Philippines, by sifting wet litter and debris near running water at altitudes of 300 and 400 m. Some of the type specimens are more or less distinctly teneral.

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.