Dendrolasiophilus subitus, Kurbatov & Kovalev, 2022

Kurbatov, Sergey A. & Kovalev, Alexey V., 2022, A new species of the genus Dendrolasiophilus Nomura, 2010 from the south of the Russian Far East (Coleoptera, Staphylinidae, Pselaphinae), Zootaxa 5100 (2), pp. 296-300 : 297-299

Dendrolasiophilus subitus sp. n.

( Figs 1–4 )

Type material. HOLOTYPE: ♂ ( ZIN): RUSSIA: Primorsky Terr., Oktyabrsky Distr., Chernyatino vill. env., 43.979920°N 131.481294°E, 26.VI.2021, at night on Quercus ? wutaishanica bark with ants Dendrolasius sp. (A. V. Kovalev).

Description. Male. Body 2.8 mm long, reddish brown, dorsally glabrous except for anterior and posterolateral margins of the head, as well as the antennae and legs.

Head (length 0.50 mm, width with eyes 0.59 mm, without eyes 0.53 mm) smooth, mostly shining, with very fine punctures on sides and at occiput. Anterior margin of frons matt, with fine wrinkles and irregular punctures, somewhat obsolete on anterior half of antennal tubercles. Anterior margin of frons and occiput with indistinct longitudinal median carina. Vertexal foveae small, located posterior to point even with posterior margin of eyes, widely spaced, distance between them about four times diameter of fovea. Longitudinal branches of frontal sulcus superficial, weakly expressed; transverse branch inconspicuous. Eyes consist of approximately 45 ommatidia, in lateral view as long as temple. Antennae 1.5 mm long; antennomeres 2–6 of subequal width, narrower than scape, following antennomeres gradually expanding towards antennal apex; antennomeres 2–7 slightly elongate, antennomere 8 barely wider than long, antennomeres 9 and 10 about as long as wide, antennomere 11 elongate ovoid, as long as 9–10 combined; antennomeres 2–6 strongly punctured, punctation of following antennomeres gradually weakened towards the antennal apex.

Pronotum (length 0.59 mm, width 0.57 mm) smooth, shining, mostly with sparse minute punctures, area posterior to antebasal foveae with distinct, although superficial punctation.

Elytra (length 0.87 mm, width 1.01 mm) smooth, shining, with punctation as on pronotum. Humeral tubercles pronounced. Left (not right) elytra next to basal fovea with another smaller fovea (probably an atavism of the second basal fovea).

Abdomen smooth and shining, visible tergites with sculpture similar to that on pronotum. Tergite 1 (IV) longest, at middle part about two times longer than tergite 2 (V); distance between its internal basal carinae about 1/6 of basal width of this segment.

Central part of metaventrite with broad roundish impression. Sternite 6 (VIII) slightly concave.

Mesotibiae with small bent apical spur. Metatrochanter with small denticle on posterior margin. Metafemora 3 ( Fig. 2 ) sub-angulate at base of posterior margin and roundly projecting near apex; posterior margin flattened and slightly concave along axis of femur; almost entire margin provided with row of long curved yellow bristles, which curve toward trochanter in basal part of femur, in distal portion curve toward apex of femur. Metatibiae ( Fig. 3 ) lacking distinct modifications.

Aedeagus ( Fig. 4 ) 0.53 mm long.

Host ant. Lasius (Dendrolasius) capitatus (Kuznetsov-Ugamsky, 1928) .

Comparative notes. Since the female of this species is not yet known, all of the following comparisons between species are given for males.

The new species is close to D. monstrotibialis and D. nishikawai by the structure of the modified metafemora. It differs from both of these species by the lack of the distinct modifications of the metatibiae and somewhat larger body sizes ( D. monstrotibialis – 2.4 mm, D. nishikawai – 2.5–2.6 mm). In addition, D. subitus sp. n. differs from D. monstrotibialis by the straight, non-emarginate mesotibiae; from D. nishikawai by the presence of an apical spur of the mesotibiae, and the presence of a denticle on the metatrochanters.

It is interesting to note that the aedeagi of the known Dendrolasiophilus species are almost identical, differing weakly in the shape of serrate apicolateral lobe and general proportions. In the species compared, the ratio of the total length of the aedeagus to the maximum width of the basal capsule is 1.85 in D. subitus , 1.75 in D. monstrotibialis , and 1.55 in D. nishikawai ; although the variability of this parameter has not yet been studied.

Etymology. The specific epithet is a Latin adjective in English meaning unexpected or sudden, reflecting the surprise discovery of this remarkable species in the Russian Far East.

Figures

FIGURE 1. Habitus of Dendrolasiophilus subitus sp. nov., male.

FIGURES 2–4. Diagnostic characters of Dendrolasiophilus subitus sp. nov., male. 2. Metafemur. 3. Metatibia. 4. Aedeagus.