Horniella hongkongensis 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 : 21-22

5. Horniella hongkongensis Yin and Li , new species

Figs 10 A, 11, 48C; Map 1

Type material (3 ♂♂, 2 ♀♀). Holotype, ♂, labeled ‘ HONG KONG, iii.1996 (HK iv.96) G. de Rougemont / Holotype [red], ♂, Horniella hongkongensis sp. n., det. Yin & Li, 2014, MHNG’ . Paratypes: 1 ♀, same label data as the holotype ( MHNG) ; 1 ♂, 1♀, labeled ‘ SBH-96/17 . HONG KONG (new Territroies): Tai Po Kau Nature Reserve [22°25’41’’N, 114°10’49’’E], après la grande place de picnic, prélèvement de sol près d’un arbre mort mais debout, 150 m; 9.xii.1996; leg. B. Hauser (extr. par app. Berlese à GE-CH) SBH-96/17 ’ ( MHNG) ; 1 ♂, labeled ‘ China: Hong Kong, New Territories , Tsuen Wan , Tai Mo Shan , forest nr. Sze Lok Yuen hostel, 22°24’18’’N, 114°07’06’’E, ca. 640 m, rotten wood, 05.iv.2013, X.B. Song leg.’ ( SNUC) .Each paratype bears a yellow type label similar to that of the holotype except ‘ Paratype [yellow] ♂ or ♀’.

Description. Male ( Fig. 10 A). Length 3.0– 3.14 mm. Head slightly longer than wide, HL 0.65–0.68 mm, HW 0.64–0.65 mm; anterolateral genal projections ( Fig. 11 C) distinct, anterior margins evenly concave; median sulcus between antennal tubercles short; scapes ( Fig. 11 B) slightly expanded at basolateral margins; clubs ( Fig. 11 A) loosely formed by apical three moderately enlarged antennomeres; venter with pair of moderately thick lateral spines ( Fig. 11 D). Maxillary palpomeres II stout, broadened at middle. Each eye composed of about 40 facets. Pronotum slightly longer than wide, PL 0.67–0.68 mm, PW 0.62–0.63 mm. Elytra wider than long, EL 0.86–0.87 mm, EW 1.23–1.29 mm; discal striae reaching apical 2/3 of elytral length. Protrochanters and profemora ( Fig. 11 E) each with one distinct ventral spine, protibiae ( Fig. 11 F) each with one small preapical denticle; mesotrochanters ( Fig. 11 G) each with one small, but distinct ventral spine, mesofemora simple, mesotibiae ( Fig. 11 H) simple; tarsomeres II normal, not extending to beneath tarsomeres III. Abdomen large, AL 0.82–0.91 mm, AW 1.46–1.50 mm, tergite IV (first visible tergite) with median carina extending to nearly half tergal length, lateral discal carinae short, tergite V lacking median carina. Sternite IX ( Fig. 11 I) nearly oval, with well-sclerotized apical half and membranous basal half. AeL 1.20–1.25 mm; aedeagus ( Figs 11 J–L) with slightly asymmetric median lobe regularly curved rightwards in dorso-ventral view; endophallus composed of one conspicuously long, twisted sclerite with pointed, curved apex, and one much shorter, nearly straight sclerite at base of long one.

Female. Similar to male in general appearance; scapes not expanded at basolateral margins; each eye composed of about 22–25 facets; profemora each with two subequal ventral spines near base, mesotrochanters lacking ventral spine. BL 3.09–3.29 mm, HL 0.67–0.70 mm, HW 0.59–0.61 mm, PL 0.67–0.68 mm, PW 0.65–0.67 mm, EL 0.79–0.82 mm, EW 1.25–1.28, AL 0.96–1.09 mm, AW 1.33–1.34 mm. Genital complex ( Fig. 48 C) with moderately sclerotized, transverse apical portion, and membranous, elongate basal portion.

Differential diagnosis. This species is placed as a member of the H. burckhardti group. All species of this group are more or less morphologically similar to each other, and can be best separated by the aedeagal structure combined with their distributions. Horniella hongkongensis shares with H. burckhardti the evenly concave anterior margins of the anterolateral genal projections, similar placement of spines on the fore and mid legs, and aedeagal form. These two species can be distinguished by the less distinctly expanded basolateral margins of the scapes, shorter median carina of tergite IV, and the aedeagal endophallus with two sclerites in H. hongkongensis , while H. burckhardti has the scapes distinctly roundly expanded at the basolateral margins, the median carina of tergite IV being extending nearly through the tergal length, and the aedeagal endophallus with one long and two short sclerites.

Comments. The slight different form of the aedeagal endophallus in the populations from Tai Po Kau (alt. ca. 250 m, Fig. 11 J) and Tai Mo Shan (alt. 640 m, Fig. 11 L) are considered intraspecific variation, while other male features are quite stable.

Distribution. South China: Hong Kong ( Map 1 ).

Collection notes. One paratype from Tai Po Kau was extracted from litter samples from a mixed broad-leaved forest by use of a Berlese funnel; the other paratype from Tai Mo Shan was collected by hand on a rotten wood.

Etymology. The specific name is taken from the type locality Hong Kong.

Figures

MAP 1. Distribution of Horniella species in China.

FIGURE 10. Male habitus of Horniella species. A. H. hongkongensis sp. n. B. H. nakhi sp. n. Scales: 1.0 mm.

FIGURE 11. Male diagnostic features of Horniella hongkongensis 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 of population from Tai Po Kau, in dorsal view. K. Same, in lateral view. L. Aedeagus of population from Tai Mo Shan, in dorsal 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.