Ostomopsis cudak, Jałoszyński & Ślipiński, 2021

Jałoszyński, Paweł & Ślipiński, Adam, 2021, Revision of the subfamily Ostomopsinae (Coleoptera: Cerylonidae), Zootaxa 4985 (4), pp. 459-481 : 466-468

Ostomopsis cudak sp. n.

( Figs 19–20 )

Type material examined. Holotype ( Thailand ): ♀, “ THAILAND: Chiang Mai / Doi Angkhang 10km W / Fang 1650m 22. IV. 87 / P. Schwendinger ” [white, printed] ( MHNG).

Diagnosis. Body uniformly light brown; elytra elongate, with EL/EW exceeding 1.3 and sides parallel in anterior half; eyes lacking; sides of pronotum lacking conspicuously long, sparse setae; median area on pronotum and median area on mesoventrite punctate; punctures on head large, sharply marked and dense, denser than those on median region of pronotum; prosternal process nearly parallel-sided with rounded distal margin; mesoventral process nearly twice as broad as prosternal process; punctures on sides of elytra in anterior half indistinctly smaller than those on median region of pronotum; scutellar shield twice as broad as long; antennomere 3 about as long as broad, 4–5 each transverse.

Description. Body of female ( Fig. 19 ) elongate oval, strongly flattened; BL 1.04 mm, BL/EW 2.18; pigmentation uniformly brown with umbra hue.

Head ( Figs 19–20 ) subtrapezoidal, HL 0.14 mm, HW 0.26 mm; vertex and frons weakly convex; eyes absent, lateral margins of head in dorsal view distinctly divergent posterad and abruptly, step-wise narrowing just in front of occiput. Vertex and frons densely covered with circular alveolate punctures of unequal diameters and slightly unevenly distributed, distances between punctures on median area from subequal to their diameters to much shorter than diameters of punctures, on sides punctures separated by spaces much narrower than their diameters; punctures on clypeus indistinct, especially anteriorly. Setae similarly dense as punctures, moderately long, nearly recumbent.

Antenna ( Figs 19–20 ) indistinctly shorter than pronotum, AnL 0.25 mm; scape weakly elongate, pedicel twice as long as broad, antennomere 3 about as long as broad, 4–8 each transverse, 9 much broader than 8 and about twice as broad as long, club about as long as broad.

Pronotum ( Fig. 19 ) broadest near posterior third, about 1.6 × as broad as head; PL 0.28 mm, PW 0.43 mm, PL/ PW 0.65; anterior margin evenly rounded; anterior corners blunt and distinctly projecting anterad; lateral margins broadly rounded and crenulate; posterior corners blunt, obtuse-angled; posterior margin weakly rounded. Narrow area along each lateral margin distinctly flattened and impunctate, with indistinct submarginal line; remaining surface of pronotum covered with alveolate circular and oval punctures of unequal diameters and slightly unevenly distributed; punctures on median region of disc similar in diameters to those on vertex and separated by spaces subequal to their diameters or wider; punctures become larger and denser toward sides, where spaces between them are much narrower than their diameters. Setae moderately dense, short, and only weakly suberect; setae on lateral pronotal margins shorter than width of flattened area along each side.

Ventral surface of prothorax ( Fig. 20 ) with prosternal process slightly longer than wide, with sides barely noticeably concave, posterior corners blunt, obtuse-angled and not projecting, and weakly, evenly rounded distal margin; entire prosternum covered with circular and oval alveolate punctures distinctly larger than those on pronotum and separated by spaces 1/2–1/4 as wide as diameters of punctures; punctures on hypomera becoming shallower and smaller toward sides of prothorax, broad area along each lateral margin impunctate, but distinctly microreticulate. Setae on prosternum sparse, short and nearly recumbent; on hypomera much shorter, barely discernible; anterior prosternal margin microcrenulate and with dense row of short setae directed anterad.

Mesoventrite ( Fig. 20 ) with mesoventral process parallel-sided between mesocoxae and nearly twice as broad as prosternal process; mesoventrite except for short procoxal rests on its anteromedian region covered with circular and oval alveolate punctures, in median area as large as the largest punctures on prosternum and nearly touching one another, between mesocoxae punctures are much smaller, but also dense.

Metaventrite ( Fig. 20 ) strongly transverse, medially slightly shorter than mesoventrite; entire surface covered with circular and oval alveolate punctures, those on median and lateromedian areas as large as the largest punctures on mesoventrite but distinctly sparser; punctures on posteromedian region distinctly smaller. Posterior metaventral margin between metacoxae slightly concave. Discrimen indiscernible.

Hind wings lacking.

Elytra ( Fig. 19 ) together oval, about 2.3 × as long as pronotum and indistinctly broader than pronotum; EL 0.63 mm, EW 0.48 mm, EL/EW 1.32. Sides barely noticeably broadening just behind humeri and largely parallel in anterior half, evenly rounded in posterior half; narrow area along each lateral margin distinctly flattened; humeri slightly obtuse-angled, humeral calli lacking; each elytron with nine longitudinal rows of small, circular punctures, those on anteromedian third with sharply defined margins, slightly smaller than largest pronotal punctures, punctures reducing in diameter toward sides and apices; remaining cuticle virtually impunctate; dorsal setae sparse, distinctly longer than those on pronotum, suberect; several sparsely distributed lateral setae distinctly longer than remaining ones. Epipleura ( Fig. 20 ) near middle length slightly narrower than width of metafemur, gradually and weakly narrowing posterad, each with undulate ridge along mesal margin.

Mesoscutellar shield ( Fig. 19 ) heart-shaped, twice as broad as long, with sides indistinctly concave just in front of broadest site, lateral corners rounded, posterior margin indistinctly angulate.

Abdominal ventrites ( Fig. 20 ) together longer than meso- and metaventrite combined; ventrite 1 slightly shorter than 2–4, with circular and oval alveolate punctures, largest on anteromedian region, where they are slightly smaller than largest punctures on metaventrite and nearly touching one another; punctures reducing in diameters and depth posterad and posterior 1/4 of ventrite remaining impunctate; ventrite 2 with transverse undulating line bearing posterior V-shaped projections, impunctate; ventrites 3–5 impunctate.

Etymology. Cudak (noun in apposition) in the Polish language ( čudák in Slovak) means “a weirdo”; this is the most bizarre of all Ostomopsis species. The name also refers to the moment of its discovery by our friend Ivan Löbl while sorting beetles at the Natural History Museum in Geneve and his exclamation to AS in Slovak “pozri sa na tohto čudáka“.

Distribution. Thailand.

Remarks. This species is unique in lacking eyes and lacking long lateral setae on the pronotum; also no other Ostomopsis species has so coarse, large and dense punctures on the head and pronotum. The body outline of O. cudak is most similar to that of O. solomon , a species also known from females only. Ostomopsis solomon , however, apart from above-mentioned differences, has a clearly different shape of the prosternal process.

Figures

FIGURES 19–20. Ostomopsis cudak sp. n. Dorsal (19) and ventral (20) habitus.