Horniella bifurca Zhang & Yin, 2021

Zhang, Wen-Xuan, Hu, Fang-Shuo & Yin, Zi-Wei, 2021, Six new species of Horniella Raffray from the Oriental region (Coleoptera, Staphylinidae, Pselaphinae), ZooKeys 1042, pp. 1-22 : 1

Horniella bifurca Zhang & Yin sp. nov. Figures 1A , 2 , 10A

Type material.

Holotype: Thailand: ♂, 'THAILAND: Chiang Mai, Pinh Khong env. 900 m, 19°26.70'N, 99°01.9'E, 14.xi.2012, M. Košťál lgt.' (MHNG). Paratype: Thailand: 1 ♀, same label data as for holotype (MHNG).

Diagnosis.

Male. Head approximately as long as wide, with distinct anterolateral genal projection, anterior margin of projection roundly emarginate; with long, apically forked ocular canthus; scape angularly expanded at anterolateral margin, antennomeres 9-11 moderately enlarged. Pronotum rounded at anterolateral margins. Protrochanter and profemur each with long ventral spine; protibia with small triangular apical spur; mesotrochanter with short but distinct ventral spine. Tergite 1 (IV) with median carina extending posteriorly for approximately 1/4 of tergal length, discal carinae long and thick. Aedeagus with asymmetric median lobe, right half of median lobe greatly protruding apicad, left half strongly curved and forked at apex; endophallus composed of two elongate, twisted sclerites.

Female. Similar to male in external morphology, profemur each with two ventral spines near base, protibia lacking preapical spur, mesotrochanter lacking ventral spine; genital complex as in Fig. 10A .

Description.

Male. Body reddish-brown, length 3.35 mm. Head (Fig. 2A ) approximately as long as wide, HL 0.69 mm, HW 0.7 mm; anterolateral genal projection distinct, anterior margin of projection roundly emarginate; antenna 1.7 mm long, scape angularly expanded at anterolateral margin, antennomeres 2-8 slightly elongate or moniliform, club loosely formed by apical three moderately enlarged antennomeres, antennomere 11 largest, approximately as long as antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 45 large facets, with long, broad forked ocular canthi (Fig. 2B ).

Pronotum as long as wide, PL and PW 0.67 mm, widest at apical 1/3; anterolateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse sulcus.

Elytra much wider than long, EL 0.91 mm, EW 1.36 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to apical 3/4 of elytral length.

Legs elongate; protrochanter (Fig. 2C ) with elongate ventral spine, profemur (Fig. 2C ) with long ventral spine near base, protibia (Fig. 2D ) with small triangular apical spur; mesotrochanter (Fig. 2E ) with short but distinct ventral spine, mesofemur (Fig. 2E ) and mesotibia (Fig. 2F ) simple.

Abdomen slightly broader than long, broadest at lateral margins of tergite 1 (IV), AL 1.08 mm, AW 1.22 mm; tergite 1 (IV) largest, as long as tergites 2 and 3 (V and VI) combined, with short median carina extending to near basal 1/4 of tergal length, discal carinae long and thick, with broad basal impression, tergite 2 (V) lacking carina, tergites 2-4 (V-VII) each with small basolateral foveae. Sternite 2 (IV) with broad basal sulcus, lacking mediobasal foveae, basolateral foveae developed as large cuticular pockets, with two pairs of antebasal protuberances, sternites 3-5 (V-VII) each with basolateral foveae, and one median and two lateral nodules, sternite 7 (IX) with well-sclerotized apical half and membranous basal half.

Aedeagus (Fig. 2G-I ) 0.61 mm long, with asymmetric median lobe, right half of median lobe greatly protruding apicad, left half elongate, with strongly curved and deeply forked apical part; endophallus composed of two elongate, twisted sclerites.

Female. General morphology similar to male, each eye composed of approximately 30 facets; profemur with two long ventral spines near base, protibia lacking preapical spur, mesotrochanter lacking ventral spine. Measurements (as for male): BL 3.08 mm, HL 0.68 mm, HW 0.61 mm, PL 0.65 mm, PW 0.63 mm, EL 0.79 mm, EW 1.17 mm, AL 0.96 mm, AW 1.2 mm. Genital complex (Fig. 10A ) with transverse apical sclerite, and elongate membranous basal portion.

Comparative notes.

This species is placed as a member of the H. centralis group. It can be readily separated from the other members of the group by the long, apically-forked ocular canthi, as well as by the unique shape of the aedeagus.

Distribution.

Thailand: Chiang Mai.

Etymology.

The new specific epithet Horniella bifurca (- us, - um) is a Latin adjective means ‘two-pronged’, referring to the apically-forked ocular canthus of the new species.

Figures

Figure 1. Dorsal habitus of Horniella species A H. bifurca sp. nov. B H. haucki sp. nov. Scale bars: 1 mm.

Figure 2. Diagnostic characters of Horniella bifurca sp. nov. A left half of head, in dorsal view B head, in lateral view C protrochanter and profemur D protibia E mesotrochanter and mesofemur F mesotibia G-I aedeagus, in dorsal (G), lateral (H), and ventral (I) view. Scale bars: 0.3 mm (A, C-F); 0.2 mm (B, G-I).

Figure 10. Female genitalia of Horniella species, in dorsal view A H. bifurca sp. nov. B H. nantouensis sp. nov. Scale bars: 0.2 mm.