Horniella sabahensis 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 sabahensis Zhang & Yin sp. nov. Figures 7A , 8

Type material.

Holotype: East Malaysia: ♂, 'Borneo: Sabah, Batu Punggul Resort, primary forest, 24.vi.-1.vii.96, Kodada lgt. / vegetation debris and forest floor litter accumulated around large trees near river.' (MHNG).

Diagnosis.

Male. Head longer than wide, anterolateral genal projections weakly developed, anterior margin of projection oblique; scape lacking expansion at lateral margin, antennomeres 9-11 moderately enlarged, forming distinct club. Pronotum rounded at lateral margins. Profemur with two tiny ventral spines near base; metatibia with preapical triangular denticle. Tergite 1 (IV) with median carina extending posteriorly for approximately 3/4 of tergal length, lacking discal carinae, tergite 2 (V) with short median carina. Aedeagus with slightly asymmetric median lobe, apical portion of median lobe narrowed, apex truncate in dorso-ventral view; endophallus lacking sclerite, composed of elongate membranous structure with many small denticles.

Description.

Male. Body reddish-brown, length 3.41 mm. Head (Fig. 8A ) longer than wide, HL 0.68 mm, HW 0.59 mm; anterolateral genal projection weakly developed, anterior margin of projection oblique; antenna 1.96 mm long, scape lacking expansion at lateral margin, antennomeres 2-8 slightly elongate or moniliform, distinct club formed by apical three enlarged antennomeres, antennomere 11 largest, slightly shorter than antennomeres 9 and 10 combined; indistinct lateral postantennal pits present; eyes prominent, each composed of approximately 40 large facets, usual area of ocular canthus only slightly prominent (Fig. 8B ).

Pronotum distinctly longer than wide, PL 0.71 mm, PW 0.6 mm; widest at middle; lateral margins rounded; disc moderately convex, finely punctate, with distinct median antebasal and lateral antebasal foveae connected by complete transverse antebasal sulcus.

Elytra much wider than long, EL 0.77 mm, EW 1.2 mm; each elytron with two large, setose basal foveae; discal striae extending from outer basal foveae to apical 2/3 of elytral length.

Legs elongate; protrochanter (Fig. 8C ) simple, profemur (Fig. 8C ) with two tiny ventral spines at base, protibia (Fig. 8D ) simple; mesotrochanter, mesofemur (Fig. 8E ) and mesotibia (Fig. 8F ) simple; metatibia (Fig. 8G ) with distinct apical triangular denticle.

Abdomen slightly longer than broad, broadest at lateral margins of tergite 1 (IV), AL 1.25 mm, AW 1.16 mm; tergite 1 (IV) largest, slightly shorter than tergites 2 and 3 (V and VI) combined, with median carina extending to near basal 3/4 of tergal length, lacking discal carinae, tergite 2 (V) with median carina extending to near basal 1/4 of tergal length, 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 nodules, sternites 3-5 (V-VII) with basolateral foveae, one median and two lateral nodules, sternite 7 (IX) nearly oval, with well-sclerotized apical half and less sclerotized basal half.

Aedeagus (Fig. 8H-J ) 0.57 mm long, with slightly asymmetric median lobe, apical part of median lobe narrowed, apex broadly truncate in dorso-ventral view; endophallus lacking strongly sclerotized structures, composed of broad, elongate membrane with numerous small denticles.

Female. Unknown.

Comparative notes.

Horniella sabahensis sp. nov. is placed as a member of the H. hirtella group. Males of this species share with H. prolixo Yin & Li from Thailand the weakly developed anterolateral genal projections, lack of an expansion at the lateral margin of the scape, and a moderately expanded preapical portion of the metatibia. They can be best separated by the larger body size (3.41 mm vs 2.95-3.02 mm), tergite V with a short median carina (lacking in H. prolixo ), as well as the much narrower apex of the aedeagus of the new species.

Distribution.

East Malaysia: Sabah.

Etymology.

The new species is named after its type locality, Sabah, East Malaysia.

Figures

Figure 7. Dorsal habitus of Horniella species A H. sabahensis sp. nov. B H. taiwanensis sp. nov. Scale bars: 1 mm.

Figure 8. Diagnostic characters of Horniella sabahensis 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 metatibia H-J aedeagus, in dorsal (H), lateral (I), and ventral (J) view. Scale bars: 0.2 mm (A, B, H-J); 0.3 mm (C-G).