Thinodromus (s. str.) improcerus Gildenkov, 2021

Gildenkov, M. Yu., 2021, A new unusually small species of the genus Thinodromus Kraatz, 1857 (Coleoptera: Staphylinidae: Oxytelinae) from Thailand, Far Eastern Entomologist 423, pp. 1-4 : 2-4

Thinodromus (s. str.) improcerus Gildenkov , sp. n.

http://zoobank.org/NomenclaturalActs/ A8253E11-07DB-4573-AD21-AF19935CDB4C

Figs 1–4

TYPE MATERIAL. Holotype – ♂, Thailand: Chayaphum Province , Tat Ton

National Park, with label “ THAILAND: 27.11.1995 Chayaphum Prov. Tat Ton NP

leg. Zettel (30)” ( NHMW). Paratype: Thailand, 1♀, with label “ THAILAND Jan .

1989 240 km NW Bangkok 110 m, leg. Thielen” (cMG).

DESCRIPTION. MALE (holotype). Length of body 2.2 mm. Dark-brown, legs and antennae yellow-brown. Integument is quite shiny, body with fairly short light-

coloured seta.

Head transverse, with a wide base, ratio of its length (from posterior margin of the head to the anterior margin of clypeus) to maximum width is about 18:29. Neck constriction is prominent. Eyes large, convex, occupying almost entire lateral side of head; temples almost indistinct, the head has the largest width in the eye area

( Fig. 1 ). Head surface with clearly, rather finely and dense punctation. Diameter of punctures is about 1.5 times smaller than the eye facet. Distances between punctures are significantly smaller than their diameter, interspaces smooth, shiny

( Fig. 1 ). Antennae rather long ( Fig. 1 ), antennal segments 1–8 elongate; segment 9

slightly elongate; segment 10 about as long as wide; segment 11 elongate, conical.

Last 3 segments more massive and form loose club.

Pronotum heart-shaped, reaches its greatest width after about 2/3 of the length measured from the base, then narrowed ( Fig. 1 ). Ratio of pronotum length to its maximum width is about 24:31. Surface of pronotum with clearly, rather finely and dense punctation. Diameter of punctures is about 1.5 times smaller than the eye facet. Distances between punctures are significantly smaller than their diameter,

interspaces smooth, shiny ( Fig. 1 ). Base of pronotal disc with distinct horseshoe-

shaped depression ( Fig. 1 ).

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aedeagus, dorsal view; 3 – the same, lateral view; 4 – spermatheca, lateral view. Scale bars for figs. 2–4 = 0.25 mm.

Ratio of length of elytra to their combined width is about 38:42. Elytra with rather delicate, rather finely and dense punctation. Diameter of punctures is about

1.5 times smaller than the eye facet. Distances between punctures significantly smaller than their diameter, interspaces smooth, shiny ( Fig. 1 ).

Abdomen with very fine and very sparse punctation, shiny. The anterior margin of tergites III, IV, and V has 4 deep round impressions.

Aedeagus of a characteristic structure ( Figs 2, 3 ).

FEMALE (paratype). Length 2.2 mm. Sexual dimorphism absent, female mor-

phologically is similar to male. Spermatheca as in Fig. 4 .

DIAGNOSIS. The species is distinguished by its small size, clear and dense punctation of the head and pronotum and the presence of four deep rounded depressions on the anterior margin of tergites III, IV and V ( Fig. 1 ). Reliably new species is distinguished from all known species of Thinodromus by the structure of the aedeagus

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ETYMOLOGY. From the Latin “ improcerus ” – “small”, the name is associated with small size.

Figures

Figs 1–4. Thinodromus (s. str.) improcerus, sp. n. 1 – male body, dorsal view; 2 –