Tyrinasius nomurai Yin and Yang

Yang, Yi-Cheng, Yin, Zi-Wei & Yu, Wei-Dong, 2012, A new species of Tyrinasius Kurbatov (Coleoptera, Staphylinidae, Pselaphinae) from Ningxia, Northwest China, Zootaxa 3401, pp. 60-62 : 60-61

Tyrinasius nomurai Yin and Yang , new species

( Figs. 1–6 )

Type material. Holotype: CHINA: male, labelled ‘ China: Ningxia A. R. / Liupanshan N. R. / Wo-Yang-Chuan / 2,400 m [berlese funnel] / Yun Bu leg.,’. Paratype: CHINA: male, same label data as holotype.

Description. Length 2.50 mm, reddish brown, maxillary palpi and tarsi lighter; broadened posteriorly, weakly flattened on dorsal surface of elytra and abdomen.

Head longer than wide, ovoid, clypeus short, slightly arcuate at anterior margin, frons convex, constricted posterior antennal bases, vertex slightly convex, nearly smooth on dorsal surface, with pair of vertexal foveae between eyes, genae weakly broadened in front of eyes, postgenae broad, distinctly rounded. Eyes each with about five facets. Antennae slender, antennomere I large, longer than wide, subcylindrical, II similar to I but smaller, III to VIII subequal in width, IX 1.2 times as long as VIII, subglobose, X larger than IX, almost globular, XI largest, as long as IX and X combined, 1.4 times as wide as X, nearly ovoid and flattened at base, weakly pointed at apex, relative length (width) of each antennomere from base to apex: 2.0(1.0): 1.7(0.9): 1.4(0.8): 1.3(0.8): 1.2(0.7): 1.2(0.8): 1.1(0.9): 1.2(0.8): 1.5(1.0): 1.7(1.2): 3.8(1.7). Maxillary palpi ( Fig. 1 ) large, palpomeres I small, II large and elongate, pedunculate, III shorter than II, pedunculate, IV largest, slightly shorter than II, ovoid and pedunculate only at base, setose at apex, apical pseudosegment well-defined.

Pronotum longer than wide, about as long as head, slightly constricted at lateral sides, pubescent on dorsal and lateral surfaces. Elytra very short, about as long as pronotum, transverse and trapezoidal, humeri almost absent, each elytron with two large well-defined basal foveae, convex along suture, weakly depressed at apex. Legs shorter and slender, tibiae slender, slightly curved close to apex, covered with dense hair at ventral margins. Metasternum strongly convex at middle, depressed between metacoxae.

Abdomen larger than elytra, wider than long, about twice length of elytra, rounded posteriorly, abdominal segment IV the widest, nearly quadrate, more than four times as long as V. Tergites IV to VI transverse and convex, V about 2/3 as long asIV in dorsal view, transverse and narrowed posteriorly, VI and VII nearly subequal in dorsal length, transverse, tergite VIII ( Fig. 2 ) trapezoidal in exposed part, sternite VIII ( Fig. 3 ) narrowed posteriorly, arcuately emarginate at posterior margin.

Aedeagus ( Figs. 4–6 ) well-sclerotized, parameres V-shaped, narrowed apicad, with two short, thin apical setae; median lobe elongate, expanded laterally before apex; endophallus long and slender.

Female. Unknown.

Distribution. Known only from the type locality.

Comparative notes. Closest to T. sichuanus in the large size and similar form of the maxillary palpi; readily separated by its aedeagus having the median lobe expanded near the apex, which in T. sichuanus is evenly narrowed from the middle toward the apex.

Etymology. We dedicate this species to Shûhei Nomura who made a major contribution to the Chinese Tyrinasius .

Figures

FIGURES 1 – 6. Major diagnostic features of T. nomurai. 1. Maxillary palpus. 2. Tergite VIII. 3. Sternite VIII. 4. Aedeagus, in dorsal view. 5. Same, in lateral view. 6. Same, in ventral view. Scales: 0.1 mm.