Besuchetaceus, , 2015

Zi-Wei Yin & Li-Zhen Li, 2015, Review of the Himalayan genus Hingstoniella Jeannel, and description of Besuchetaceus gen. n. from Nepal (Coleoptera: Staphylinidae: Pselaphinae), Revue suisse de Zoologie 122 (1), pp. 165-180 : 175

Besuchetaceus gen. n.

Figs 8-9

Type species: Besuchetaceus nepalensis sp. n.

Diagnosis: Head nearly triangular; frontal rostrum low; with distinct vertexal foveae; antennomeres XI elongate and conical. Pronotum transverse, with big lateral antebasal foveae; antebasal spines present; lateral margins spinose. Each elytron with three basal foveae, shallow and short discal striae present. Abdomen with lateral margins of tergite IV edged by marginal carinae; tergite IV longest.

Description: General body form elongate; Length 3.74- 3.93 mm. Head nearly triangular ( Fig. 8 A); with low frontal rostrum, antennal tubercles slightly prominent; large vertexal foveae connected by broad U-shaped vertexal sulcus; antennae with 11 antennomeres, clubs loosely formed by apical three antennomeres, antennomeres XI elongate and conical; ocularmandibular carinae distinct; eyes reniform ( Fig. 8 B); maxillary palpi with palpomeres III transverse and triangular, IV fusiform; with gular foveae merged into single opening ( Fig. 8 C). Pronotum ( Fig. 8 D) transverse; lateral antebasal foveae distinct, lateral margins spinose, lacking median antebasal fovea, with median and lateral longitudinal sulci, antebasal spines present; disc moderately convex; lacking basolateral foveae; lacking paranotal carinae; lateral procoxal foveae ( Fig. 8 E) present. Each elytron ( Fig. 8 F) with three distinct basal foveae, discal striae short and shallow, sutural striae complete; with subhumeral foveae, marginal stria present from fovea toward posterior margin; lateroapical notch small. Thorax ( Fig. 9 A) with small median and lateral mesoventral foveae; with lateral mesocoxal foveae; lacking prepectal foveae; lateral metaventral foveae small, metacoxae narrowly separated; posterior margin with narrow median notch. Abdomen ( Fig. 9 B-D) with tergites IV (first visible tergite), V, and VII bearing marginal carinae extending through whole tergal length; tergite IV longest, V-VII successively shorter; tergite IV with basolateral foveae at lateral ends of sulcus, lacking mediobasal foveae and discal carinae, V-VII each with one pair of basolateral foveae. Sternite IV (second visible ventrite) twice length of V at midlength, with one pair of mediobasal foveae and three pairs of basolateral foveae, basal sulcus between each mediobasal fovea and first pair of basolateral fovea, sternites V-VII lacking fovea. Legs slender, second and third tarsomeres subequal in length.

Male with vertex modified. Aedeagus with paramere fused to median lobe to form elongate ventral lobe; articulated dorsal lobe present; basal capsule with strongly constricted base.

Comparative notes: This new genus is placed as a member of the Hingstoniella group by the shared modified male vertex and the unique type of aedeagus. Besuchetaceus is most close to Sinotrisus by the similar general appearance, and each elytron possessing three basal foveae. The two genera can be separated by the spinose pronotal lateral margins, the shallow, complete basal sulcus, and the lack of discal carinae on tergite IV in Besuchetaceus , and the pronotum is generally more transverse. Sinotrisus has the pronotal lateral margins lacking spines or denticles, the pronotum is much less transverse, and tergite VI bears a deep basal sulcus interrupted by discal carinae or ridges. Besuchetaceus can be separated from Hingstoniella by the less robust habitus, the quite different shape of the pronotum, and the presence of three basal foveae on each elytron.

Etymology: The new genus is named after Claude Besuchet (Geneva, Switzerland), who firstly recognized this as a new genus placed near Hingstoniella , and added an identification label. Gender is masculine.