Labomimus cavicornis, Yin & Li, 2021

Yin, Zi-Wei & Li, Ning, 2021, Eight new species and additional records of the Pselaphodes complex from Laos and Vietnam, with a key to known species (Coleoptera: Staphylinidae: Pselaphinae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 61 (1), pp. 35-53 : 37

Labomimus cavicornis sp. nov.

( Figs 1A , 2 )

Type material (6 specimens). HOLOTYPE: VIETNAM: ĐỒNG NAI: ♂, ‘S-VIETNAM, Nam Cat Tien Nat. Park , 1.- 15.5.1994, Pacholatko & Dembicky’ ( MHNG) . PARATYPES: VIETNAM: ĐỒNG NAI: 5 ♂♂, same label data as for holotype ( MHNG, SNUC) .

Diagnosis. Male body length 3.09–3.23 mm. Antennomere 9 with broad depression in apical half, with disc-like impression inside depression; antennomeres 10 broadly depressed and antennomere 11 deeply concave on ventral side. Horn-like metaventral processes in lateral view elongate and bifurcate at apices. Protibia with short, blunt preapical projection; mesotrochanter with acute ventral spine. Median lobe of aedeagus asymmetric, narrowing apically; parameres broad at bases and narrowed in apical halves; endophallus with spine-like structures and one elongate sclerite. Female unknown.

Description. Male ( Fig. 1A ). Body length 3.09–3.23 mm. Head slightly broader than long, HL 0.56–0.61 mm, HW 0.59–0.63 mm; eyes prominent, each composed of about 41 facets. Antennomeres 2–8 of similar shape, each moniliform; antennomeres 9–11 ( Fig. 2A ) forming distinct club; antennomere 9 with large depression in apical half, and one disc-like impression inside depression; antennomeres 10 broadly depressed and antennomeres 11 with broad and deep concavity on ventral side. Pronotum ( Fig. 2B ) approximately as long as wide, PL 0.56 mm, PW 0.56–0.59 mm, narrowed anteriorly at apical 2/5. Elytra broader than long, EL 0.87–0.94 mm, EW 1.11–1.15 mm. Horn-like metaventral processes ( Fig. 2C ) in lateral view elongate and curved upward, bifurcate at apices. Protrochanter ( Fig. 2D ) with tiny ventral tooth; profemur angularly expanded at middle; protibia ( Fig. 2E ) with blunt process before apex; mesotrochanter ( Fig. 2F ) with acute ventral spine; mesofemur ( Fig. 2F ), metatrochanter and metafemur ( Fig. 2G ) simple.Abdomen broad at base and narrowed apically, AL 1.00– 1.02 mm, AW 1.11–1.20 mm. Sternite 7 (IX) ( Fig. 2H ) hemi-membranous, elongately oval. Aedeagus ( Figs 2I –E ) 0.55 mm long; median lobe asymmetric dorso-ventrally, narrowing apically; parameres short, curved ventrally, broad at bases and abruptly narrowed for apical halves; endophallus comprising one large, elongate and curved sclerite, and numerous hemi-membranous spinelike structures at apical part.

Female. Unknown.

Comparative notes. This is a very distinctive species which can be easily separated from all congeners by unique modification of the male antennal club.

Etymology. The new species is a Latin adjective composed of cavus (- a, - um; meaning hollow, concave, excavated) and cornis (- is, - e; meaning horned), referring to the strongly depressed and concave antennal clubs of the male.

Distribution. Vietnam: Đồng Nai.

Figures

Fig. 1. Dorsal habitus of Labomimus males. A – L. cavicornis sp. nov.; B – L. cucphuong sp. nov. Scale bars: 1 mm.

Fig. 2. Male diagnostic features of Labomimus cavicornis sp. nov.A – left antennal club, in lateroventral view; B – pronotum; C – metaventral process, in lateral view; D – protrochanter and profemur; E – apex of protibia; F – mesotrochanter and mesofemur; G – metatrochanter and metafemur; H – sternite 7 (IX); I–K – aedeagus, in dorsal (I), lateral (J), and ventral (K) view. Scale bars: 0.3 mm in A, B, D, F, G; 0.2 mm in C, I, J, K; 0.1 mm in H; 0.05 mm in E.