Archelamprosomius kirejtshuki, Bukejs, Andris & Nadein, Konstantin, 2015

Bukejs, Andris & Nadein, Konstantin, 2015, First fossil Lamprosomatinae leaf beetles (Coleoptera: Chrysomelidae) with descriptions of new genera and species from Baltic amber, Zootaxa 3931 (1), pp. 127-139 : 135-136

Archelamprosomius kirejtshuki sp. nov.

( Figs 11–13 ; 17–18)

Types. Holotype: “Nr. 033” [white printed label], “ Holotype / Archelamprosomius kirejtshuki sp. nov. / Bukejs & Nadein des.” [red printed label]; sex unknown. A rather complete beetle, though with missing right antenna; ventral surface of the specimen is partially obscured by a “milky” opacity. The specimen is embedded in a small, oval piece of amber (length about 26 mm, max. width 11 mm). There are few small pieces of organic material, small gas bubbles and cracks diffusely spread throughout the amber, though other animals and plant syninclusions are absent.

Type strata. Baltic Amber, Upper Eocene, Prussian Formation.

Type locality. Baltic Sea coast, Yantarny village [formerly Palmnicken], Kaliningrad Region, Russia.

Etymology. The epithet of this new species is devoted to our dear colleague, Alexander G. Kirejtshuk (St. Petersburg, Russia), an acknowledged specialist in fossil Coleoptera .

Description. Body length ca. 3.0 mm, maximum width ca. 2.0 mm; broadly oval, convex dorsally, flat ventrally; unicolorous black; glabrous.

Head with fine, smoothed punctation; flat laterally; vertex without longitudinal median groove. Eyes entire, not notched, relatively small (vertical diameter less than half as gtreat as length of lateral margin of pronotum), weakly convex, with distinct facets; vertical diameter 1.6 times as great as transverse diameter. Distance between eyes nearly as two vertical diameters of one eye. Antennae not visible.

Pronotum transverse, widest at base; lateral margins approximately straight in lateral view, anterior margin arcuate in frontal view, basal margin weakly sinuate; all margins with carinate borders; anterior angles acute, bent ventrally and not visible from above, posterior angles nearly straight. Pronotal punctation very fine, relatively sparse, subuniform; distance between punctures 3–5 puncture diameter. Prohypomera shagreened. Procoxal cavity open posteriorly. Procoxae oval, transverse.

Scutellum minute, triangular with rounded apex. Humeral calli well developed. Elytral punctures moderatelysized (distinctly larger than those on pronotum), dense, punctures shallower at apex; primary punctures arranged in somewhat irregular longitudinal rows, distance between them 0.5–1.5 puncture diameter; intervals flat, with additional punctures, nearly as large as primary, confused, and slightly different from punctures in rows. Epipleura horizontal (not visible in lateral view), narrow (anteriorly wider and gradually narrowing posteriorly), with strongly produced and convex projection in anterior 1/3. Macropterous.

Metepisternum shagreened. Abdomen with ventrite 1 longest, about as long as ventrites 2–3 combined; ventrite 2 slightly longer than ventrite 3, ventrites 3–4 subequal in length; ventrite 5 approximately 1.8 times as long as preceding ventrite; anterior and posterior margins of all ventrites (except widely rounded apex of ventrite 5) almost straight medially distinctly curved towards apex laterally. Surface shagreened, with fine, sparse punctures (ventrite 5 covered with denser punctures) and fine, pale, short, recumbent setae (especially distinct at distal margin of ventrite 5). Pygidium completely covered by elytra.

Legs relatively short and robust; femora and tibiae with fine punctures and shagreened. Femora weakly swollen in the middle. Tibiae flattened, not widened apically; with short, fine, pale, recumbent setae, apically with distinctly longer semierect pale setae. Femora and tibiae subequal in length. Tarsomeres 1–3 of all legs distinctly dilated; tarsomere 3 deeply bilobed; tarsomere 4 projecting between lobes of tarsomere 3 reaching the middle of lobes.

Comparison. This new species differs from Archelamprosomius balticus sp. nov. in its slightly longer legs, tibiae not widened apically, larger elytral punctures, strongly confused punctural rows, subuniform elytral punctation.

Figures

FIGURES 11 – 13. Archelamprosomius kirejtshuki sp. nov., holotype: 11 — habitus, ventro-lateral view; 12 — details of forebody; 13 — habitus, dorso-apical view.