Horaeomorphus biwenxuani D.-Y. Zhou & S.-J. Zhang

Zhou, De-Yao, Zhang, Su-Jiong & Li, Li-Zhen, 2016, Contributions to the knowledge of the genus Horaeomorphus Schaufuss (Coleoptera, Staphylinidae, Scydmaeninae) in mainland China, ZooKeys 572, pp. 51-70: 59-62

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Horaeomorphus biwenxuani D.-Y. Zhou & S.-J. Zhang

sp. n.

Taxon classification Animalia Coleoptera Staphylinidae

Horaeomorphus biwenxuani D.-Y. Zhou & S.-J. Zhang  sp. n. Fig. 8

Type material

(1 ♂). Holotype: CHINA: ♂, labeled 'China: Xizang Prov., Cuona County [错那县], Lexiang [勒乡], alt. 2500m, 15.vii.2012, Wen-Xuan Bi leg.'.


Horaeomorphus biwenxuani  can be readily separated from all other congeners by its moderately large (2.78 mm) and elongate body, small pronotum lacking basal groove, with a row of three dorsal pits, subtriangular metatrochanter with distal edge produced into a short acute spine, and slender aedeagus with a complicated and strongly asymmetrical endophallus.


Male. BL 2.78 mm; body (Fig. 8A) large, slightly convex, dark reddish-brown, legs and palpi slightly lighter. Head broadest at large, finely faceted and moderately convex eyes, HL 0.41 mm, HW 0.58 mm; tempora rounded, about as long as length of eye in dorsal view; vertex strongly transverse and weakly convex, with pair of small but distinct pits located near posterior margins of supra-antennal tubercles; frons weakly convex; supra-antennal tubercles strongly raised. Punctation on vertex and frons sparse, small but distinct; setae moderately long, sparse. Antennae (Fig. 8B) short, AnL 1.18 mm, relative lengths of antennomeres: 0.9 : 1.0 : 1.6 : 1.3 : 1.1 : 1.0 : 0.8 : 0.9 : 1.0 : 1.1 : 1.7. Pronotum short, longer than wide, widest slightly behind anterior fourth, PL 0.77 mm, PWm 0.65 mm, PWb 0.53 mm; pronotal margin rounded near anterior 2/3, then nearly straight up to sub-basal constriction; base with row of three dorsal pits and pair of lateral impressions located in constriction. Punctation on disc sparse and fine; dorsal surface glossy; setation moderately long. Elytra elongate, more convex than pronotum, distinctly impressed in middle at about anterior third; widest near anterior 2/5, narrowing toward apices. EL 1.59 mm, EW 0.99 mm, EI 0.59. Humeral calli distinct. Punctures fine, more distinct than those on pronotum, sharply marked and separated by spaces 3 –4× as wide as puncture diameters; setation moderately dense. Hindwings fully developed. Metatrochanter (Fig. 8I) short, subtriangular, distal edge produced into short acute spine. Aedeagus (Fig. 8 C–E) slender, AeL 0.55 mm; endophallus (Fig. 8 G–H) strongly asymmetrical, with curved axial component protruding from posterior complicated structure surrounded by two lateral Λ-shaped structures; parameres (Fig. 8F) very slender with broadened apical parts, slightly shorter than median lobe, each with nine apical and subapical setae.

Female. Unknown.


This new species with remarkably long legs has subtriangular metatrochanters in males, each with a sharp distal edge. This unique character can be found also in all four known Nepalese congeners: Horaeomorphus obrus  Vít, 2004, Horaeomorphus deharvengi  Vít, 2004, Horaeomorphus himalayensis  Franz, 1974 and Horaeomorphus nepalensis  Franz, 1973 ( Franz 1974; Vít 2004), but so far has not been recorded in Horaeomorphus  outside the Himalayas. However, a relatively small body (2.78 mm; among Himalayan species only Horaeomorphus deharvengi  can be smaller than 3mm) and strongly asymmetrical endophallus are clearly different from characters of the Nepalese species. An asymmetrical endophallus also occurrs in Horaeomorphus deformatus  Jałoszyński, 2006 (W Malaysia: Kuala Terengganu), Horaeomorphus pseudosabahensis  Jałoszyński, 2006 (E Malaysia: Sabah, Sarawak) and Horaeomorphus minor  Jałoszyński, 2009 (the Philippines: Bukidnon, Mindanao), but its structure is distinctly different from that in Horaeomorphus biwenxuani  .


Western China: Xizang.


This species is dedicated to Wen-Xuan Bi, who collected the type specimen.