Nipponobythus alienoceps, Yin, 2020

Yin, Zi-Wei, 2020, New species of karst-dwelling Pselaphinae from southwestern China (Coleoptera: Staphylinidae), Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 163-168 : 165-166

Nipponobythus alienoceps sp. nov.

( Fig. 2 )

Type material. HOLOTYPE:, ‘ CHINA: SW China: Guizhou, Pingtang County ( ỸṚH), Wanzi Village ( ḾTIJ), Ba-mao-chong (ƂĿṖ), Ganxiao Cave ( Ȓ ḊḌ), N27°46 ′ 17.18 ′′, E107°17 ′ 39.26 ′′, ca. 1,200 m, 6.x.2019, Yun-Chun Li leg.’ ( SNUC) . PARATYPES: CHINA: 3 ♀♀, same label data as holotype ( SNUC).

Diagnosis. Body length 1.65–1.81 mm; with dense, moderately long pubescence on head, pronotum, and elytra; male with strongly modified vertex and frons comprising complicated structures, vertex laterally with large setose area; female with head unmodified, frons roughly punctate instead; aedeagus symmetrical, apices of parameres pointed, endophallus mainly composed of weakly to strongly sclerotized spine-like structures.

Description. Male ( Fig. 2A ). Body reddish-brown, length (from anterior margin of clypeus to apex of abdomen) 1.65 mm. Head ( Fig. 2B ) sub-rectangular and strongly transverse, length from anterior margin of clypeus to head base 0.35 mm, maximum width across eyes 0.43 mm; vertex finely punctate, densely pubescent, strongly concave at middle, with pair of markedly raised projections each densely setose apically, anterior area deeply and transversely sulcate, lateral portions covered by dense, short setae; antennal tubercles only faintly raised; frons abruptly elevated at middle, forming vertical plane with clypeus; each eye composed of about 45 facets; antennae relatively elongate, length 0.68 mm, with distinct club formed by apical three antennomeres; antennomere 1 and 2 distinctly larger than antennomeres 3–8, antennomere 3 elongate, antennomeres 4–8 each moniliform, antennomere 9 approximately twice size of 8, subconical, antennomere 10 subconical and strongly transverse, antennomere 11 largest, broadest near middle and narrowing apically. Pronotum with moderately dense pubescence; slightly wider than long, length along midline 0.33 mm, maximum width 0.37 mm; with complete transverse antebasal sulcus connecting foveae, with nine short longitudinal ridges at base. Elytra much wider than long, length along suture 0.51 mm, maximum width 0.69 mm, dorsal surface with dense, long setae; each elytron with two nude foveae; sutural sulcus complete, lacking discal longitudinal sulcus. Legs simple, without protuberances. Abdomen wider than long, length along midline 0.64 mm, maximum width 0.42 mm; tergite IV (first visible tergite) with short discal carinae widely separated; both inner and outer marginal carinae complete and parallel; tergite VIII ( Fig. 2C ) strongly transverse, with two lateral and one middle projection along anterior margin; sternite IX ( Fig. 2D ) composed of two weakly-sclerotized, elongate plates. Length of aedeagus ( Figs 2E, 2F ) 0.24 mm (including parameres), median lobe and parameres symmetrical; each paramere roundly transverse and with pointed apex on posterior margin; endophallus with numerous weakly-sclerotized spine-like structure at middle portion, and with more elongate and more strongly sclerotized spines, and one elongate sclerite at basal portion.

Female. Similar to male in general appearance; head lacking modification, anterior portion of frons roughly punctate; each eye composed of about 8 facets. Measurements (as for male): body length 1.77–1.81 mm; length of head 0.34–0.37 mm, width 0.37–0.41 mm; length of antennae 0.67–0.70 mm; length of pronotum 0.32–0.33 mm; width 0.34–0.35 mm; length of elytra 0.45 mm, width 0.65–0.67 mm; length of abdomen 0.64 mm, width 0.43–0.48 mm.

Comparative notes. This is a very distinct species which can be easily separated from all congeners by the unique form of the sexually modified head of the male, and the configuration of the aedeagus.

Etymology. The new specific epithet alienoceps is an adjective combined from Latin ‘ aliēnus (exotic, foreign) and ‘- ceps (-headed)’, referring to the strongly modified head of the male.

Distribution. Southwestern China: Guizhou.

Comments. Two Japanese species, i.e., N. latifrons Jeannel, 1958, and N. plagiatus Jeannel, 1958, have been reported to inhabit cave environments ( JEANNEL 1958; TA- NOKUCHI 1985). In Guizhou all individuals of N. alienoceps sp. nov. were collected under a few decomposing sticks on wet ground in a completely dark environment deep within the cave (Y.-C. Li, pers. comm.).

Figures

Fig. 2. Nipponobythus alienoceps sp. nov., male. A – habitus; B – head dorsum; C – tergite VIII; D – sternite IX; E–F – aedeagus, ventral. Scale bars: 0.5 mm in A; 0.2 mm in B; 0.1 mm in C–F.