Horniella asymmetrica Yin and Li

Yin, Zi-Wei & Li, Li-Zhen, 2014, Revision of the Oriental genus Horniella Raffray (Coleoptera, Staphylinidae, Pselaphinae), Zootaxa 3850 (1), pp. 1-83 : 42-45

13. Horniella asymmetrica Yin and Li , new species

Figs 24 A, 25, 48H; Map 4

Type material (2 ♂♂, 5 ♀♀). Holotype, ♂, labeled ‘ THAILAND, Khao Yai Nat. Park , 26.xi–3.xii.1985, 750– 850 m, Burckhardt-Löbl / Holotype [red], ♂, Horniella asymmetrica sp. n., det. Yin & Li, 2014, MHNG’ . Paratypes: 1 ♂, 3 ♀♀, same data as the holotype ; 1 ♀, labeled ‘ THAILAND: Khao Yai Nat. Park , 4.–5.v.1978, P. Schwendinger’ ; 1 ♀, labeled ‘ THAILAND: Chanthaburi, Khao Sabap Nat. Park , 150–300 m, 23–24.xi.1985, Burckhardt-Löbl’ . All paratypes are housed in MHNG, and each bears a yellow type label similar to that of the holotype except ‘ PARATYPE ♂ (or ♀)’.

Description. Male ( Fig. 24 A). Length 3.03–3.15 mm. Head about as long as wide, HL 0.65–0.67 mm, HW 0.63–0.64 mm; anterolateral genal projections ( Fig. 25 C) distinct, anterior margins deeply and roundly concave; median sulcus between antennal tubercles short; scapes ( Fig. 25 B) with angulate expansion at basolateral margins; clubs ( Fig. 25 A) loosely formed by apical three moderately enlarged antennomeres; venter with pair of thick lateral spines ( Fig. 25 D). Maxillary palpomeres II stout, widest near middle. Each eye composed of about 48 facets. Pronotum slightly longer than wide, PL 0.63–0.65 mm, PW 0.60–0.61 mm. Elytra wider than long, EL 0.81–0.87 mm, EW 1.26–1.29 mm; discal striae reaching apical 3/4 of elytral length. Protrochanters and profemora ( Fig. 25 E) each with one long ventral spine, protibiae ( Fig. 25 F) each with small triangular preapical denticle; mesotrochanters ( Fig. 25 G) with large, apically truncate ventral projection, mesofemora simple, mesotibiae ( Fig. 25 H) with small bluntly triangular preapical denticle; tarsomeres II normal, not extending to beneath tarsomeres III. Abdomen large, AL 0.94–0.96 mm, AW 1.27–1.28 mm, tergite IV (first visible tergite) with median carina extending to half tergal length, lacking lateral discal carinae, tergite V lacking median carina. Sternite IX ( Fig. 25 I) elongate, with well-sclerotized apical half, and membranous basal half. AeL 0.63 mm; aedeagus ( Figs 25 J–L) with strongly asymmetric median lobe conspicuously cured toward right at apex; endophallus composed of three sclerites: one broad sclerite with curved branch at middle, one elongate, curved sclerite overlapping with broad one at base, and one much shorter sclerite beside elongate one.

Female. Similar to male in general appearance; each eye composed of about 25–30 facets; profemora each with two ventral spines near base, apices of pro- and mesotibiae lacking denticle. BL 2.84–3.09 mm, HL 0.64–0.67 mm, HW 0.55–0.58 mm, PL 0.59–0.61 mm, PW 0.58–0.61 mm, EL 0.70–0.78 mm, EW 1.17–1.26, AL 0.91–1.03 mm, AW 1.19–1.31 mm. Genital complex ( Fig. 48 H) weakly sclerotized, with transverse apical sclerite.

Differential diagnosis. This distinctive species is placed as a member of the H. burckhardti group. The relatively large compound eyes, and the large, apically truncate ventral projection of the mesotrochanters are unique, which when combined with the strongly asymmetric form of the aedeagal median lobe lead to a ready separation of H. asymmetrica from all other congeners of the group.

Distribution. Thailand: Prachin Buri, Chanthaburi ( Map 4 ).

Collection notes. Adults were collected from leaf litter samples by sifting and use of Winkler-Moczarski extractors.

Etymology. The specific name ‘ asymmetrica ’ refers to the strongly asymmetric aedeagal median lobe of the new species.

Figures

MAP 4. Distribution of Horniella species in Thailand.

FIGURE 24. Male habitus of Horniella species. A. H. asymmetrica sp. n. B. H. burckhardti sp. n. Scales: 1.0 mm.

FIGURE 25. Male diagnostic features of Horniella asymmetrica sp. n. A. Antenna. B. Scape. C. Right half of head, in dorsal view. D. Head, in lateral view. E. Protrochanter and profemur. F. Protibia. G. Mesotrochanter and mesofemur. H. Mesotibia. I. Sternite IX. J. Aedeagus, in dorsal view. K. Same, in lateral view. L. Same, in ventral view. Scales: 0.3 mm, except B, I = 0.1 mm.

FIGURE 48. Female genital complex of Horniella species, in dorsal view. A. H. centralis (Population from Daba Shan). B. H. centralis (Population from Qinling). C. H. hongkongensis. D. H. nakhi. E. H. sichuanica. F. H. himalayica. G. H. hirtella. H. H. asymmetrica. I. H. burckhardti. Scales: 0.2 mm.