Obesoconnus pallidus, Jałoszyński, 2023

Jałoszyński, Paweł, 2023, Discovery of Obesoconnus Jałoszyński in the Oriental Region (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5293 (2), pp. 371-378 : 376

Obesoconnus pallidus sp. n.

( Figs 2 , 10–14 )

Material studied. Holotype: ♁ THAILAND: two labels: “ NLTx6 (5m): 16 km pt. / Kaeng Krachan NP / [W THAILAND] / 25.x.2010, S. Nomura leg.” [white, printed], “ OBESOCONNUS / pallidus m. / Jałoszyński, 2023 / HOLOTYPUS” [red, printed) ( NSMT].

Diagnosis. Aedeagus symmetrical, with pair of short subtriangular apical projections barely protruding from ostium.

Description. Body of male ( Fig. 2 ) stout and strongly convex, with moderately long appendages, glossy, BL 0.93 mm; pigmentation uniformly light brown, appendages slightly lighter, vestiture of setae light brown.

Head short, broadest at eyes, HL 0.12 mm, HW 0.20 mm; vertex and frons confluent and weakly convex; supraantennal tubercles small and feebly elevated, but each accentuated by minute impression on its posteromesal margin. Eyes extremely large, oval with narrow posteromedian emargination, coarsely faceted and strongly convex. Punctures on vertex and frons fine and shallow but distinct, separated by spaces subequal to their diameters; setae short and sparse, recumbent to suberect. Antennae slender but short, weakly thickened distally, AnL 0.30 mm; scape and pedicel strongly elongate, antennomere III indistinctly transverse, IV–VI each about as long as broad, VII–X each weakly transverse, XI subequal in length to IX–X combined, about 1.5 × as long as broad, indistinctly asymmetrical, with blunt apex.

Pronotum subtrapezoidal, equally broad between base and anterior third, PL 0.25 mm, PW 0.28 mm; anterior margin broadly rounded, lateral margins nearly straight and barely discernibly microserrate, posterior margin nearly straight; base with shallow and diffuse transverse groove indistinctly deepened at each end, and with one pair of distinct, deep, elongate lateral impressions; pronotal disc covered with punctures more distinct than those on head, small and shallow but sharply marked, separated by spaces subequal to their diameters, and with sparse, short, suberect setae.

Elytra oval, evenly convex, broadest slightly in front of middle, EL 0.55 mm, EW 0.45 mm, EI 1.22; humeral calli small, elongate, elytral apices separately rounded; punctures smaller and denser than those on pronotal disc, shallow and diffuse, superficial; setae sparse, short, suberect.

Legs moderately long and slender, unmodified.

Aedeagus ( Figs 10–13 ) moderately darkly sclerotized except for darker apical region around ostium, AeL 0.20 mm; stout, symmetrical, in ventral view barrel-shaped with broadly and shallowly emarginate apex; pair of apical projections present, short and subtriangular; parameres long and slender, symmetrical, not exceeding apex of median lobe, each with one short subapical seta.

Female. Unknown.

Distribution ( Fig. 14 ). Thailand.

Etymology. The name pallidus refers to the pale pigmentation of the holotype, distinctly lighter than that of all remaining species.

Remarks. This species has a stout, symmetrical median lobe with an exceptionally short pair of apical projections, and this structure is unique among known members of Obesoconnus .

The abbreviation “NLT” used in label indicates a light trap set at ~ 5 m above the ground on a tree in forest (S. Nomura, email dated 06.04.2023).

Figures

FIGURE 14. Distribution of nominal Obesoconnus species, with comparison of aedeagi and dorsal habitus of males.

FIGURES 1–2. Obesoconnus asymmetricus sp. n. (1); and O. pallidus (2), dorsal habitus of holotype males.

FIGURES 6–13. Obesoconnus asymmetricus sp. n. (6–9); and O. pallidus (10–13), aedeagus in ventral (6, 8, 10, 12) and lateral (7, 9, 11, 13) views.