Dilatapolochrus vikhrevi Tshernyshev, 2021

Tshernyshev, Sergei E., 2021, Dilatapalochrus gen. nov. - a new species and a new genus of soft-winged flower beetle of the tribe Apalochrini (Coleoptera: Malachiidae) from East Africa, Zootaxa 4966 (3), pp. 376-384 : 379-381

Dilatapolochrus vikhrevi Tshernyshev sp. nov.

( Figs 1–13 )

urn:lsid:zoobank.org:act:3AC1B444-C24F-47E4-BA78-54C186738DBF

Type material examined. Tanzania: Holotype, male, 15 km N of Njombe, alt. 1850 m a.s.l., 9°12’14’’S; 34°47’2’’E; 16.XII.2015, N. Vikhrev leg. ( ZIN); allotype, female (teneral), idem ( ZIN); paratypes, 10 males, idem ( ZIN, SCH); paratype, 1 male, Uzungwa Mountains , Kiranzi Kitunguru Catchment F. R., alt. 1700 m a.s.l., 8°07’S; 36°04’E; March–April 1996, L. Sørensen leg. ( ZMUC).

Description. Holotype, male ( Figs 1, 2 ). Body elongate, oval, slightly expanded posteriorly, elytra not covering three ultimate segments of the abdomen.

Body black-brown with a weak green-blue metallic luster, second antennomere and apical part of the first antennomere, clypeus and commissure membranes of ventrites yellow. Surface evenly covered with pale brown pubescence, long and erect, head also with semi-erect pale hairs. Vesicles yellow, and thoracic mesepimera blackbrown.

Head narrower than pronotum, flat, interocular area almost completely flat, eyes simple, not large, slightly protruding, round-oval, frons flat; genae short and straight; clypeus slightly elongate, transverse, straight; labrum narrow, transverse; palpi simple with apical segment slightly elongate, narrow, sub-oval and truncate at apex; surface of head evenly and finely punctured with distinct microsculpture, densely covered with short pale brown fine adpressed pubescence.

Antennae with flattened and widened 6th to 11th antennomeres ( Fig. 3 ), 2.3 mm long, expanding over the base of elytra; 1st antennomere slightly enlarged, subrectangular with rounded angles, 2nd antennomere small, round, almost completely invisible, strongly hidden by the 1st antennomere, 3rd antennomere elongate, as long as the 1st antennomere and 1.5 times narrower, 3rd, 4th and 5th antennomeres short, subtriangular, 6th to 10th with expanded outer edges, 6th and 10th triangular, 7th to 9th antennomeres rectangular and 11th (apical one) elongate and oval, widened to apex; surface sparsely covered with fine short, brown adpressed pubescence.

Pronotum weakly narrowed at base, almost completely equilateral and sub-oval with evenly rounded angles, slightly depressed at the base and at the posterior angles, with posterior margin slightly elevate and swollen; anterior and posterior margins straight; lateral sides evenly rounded and flattened, distinctly marginate; very sparsely and finely punctured lacking microsculpture, shining, evenly covered with fine long erect pale brown hairs.

Scutellum rectangular, small and narrow, transverse, almost completely covered by pronotum, sparsely punctured and covered with brown short pubescence.

Elytra sub-oval, not covering three apical segments of the abdomen, slightly expanded just behind the base, at base not wider than pronotum, humeri small, distinct and protruding; apices evenly rounded, simple; disc distinctly and finely marginate on external sides and widely along suture, edge of suture is restricted near apices of elytra; surface shining, densely and coarsely punctured, with distinct microsculpture, evenly covered with pale-brown long erect pubescence.

Hind wings normal.

Legs thin, slightly elongate; posterior femora almost completely reaching elytral apices; anterior tibiae dilated and strongly excavated in apical half so the basal lobe appears to have a flattened oval plate above ( Figs 5, 6 ), intermediate tibiae stout, with three deep round-oval impressions near apices at ventral side ( Figs 7, 8 ), posterior tibiae simple, straight; anterior femora slightly widened and evenly impressed in middle, sides of the impression covered with a row of short erect hairs ( Fig. 5 ), all other femora slightly widened and simple, lacking emarginations or indentations; trochanters simple, lacking teeth, elongate; all tarsi 5-segmented, intermediate tarsomeres slightly compressed, apical one flattened, not long, first tarsomere elongate, sub-triangular and the longest of all legs, 2nd segment in anterior tarsi triangular, with small transversal comb above ( Fig. 4 ), in intermediate and posterior legs it is 1.3 times shorter than the 1st tarsomere, 1.3 times as long as the 3rd and twice as long as the 4th; the 3rd and 4th tarsomeres in anterior legs small, equal in length and each twice as short as the 2nd tarsomere; claw-segment elongate and narrow in all legs; claws short, thin, narrow and sharp, with round transparent membrane at base.

Ventral body surface evenly punctured, lacking microsculpture, evenly covered with long and fine, adpressed goldish pubescence; metathorax swollen, lacking appendage of hair tuft. Pygidium undivided, evenly rounded distally ( Fig. 9 ); 8th ultimate abdominal ventrite looks bilaciniated, but both lobes distinctly adjoined, evenly rounded and narrowed distally, with triangular emargination in middle ( Fig. 10 ); aedeagus almost completely straight, strongly narrowed distally, spiculate, with elongate narrow and slightly roundly flattened apical lamella; two groups of dark long sharp and narrow bristles are visible in distal part near both sides of the inner sac ( Fig. 11 ). Tegmen narrow, elongate, with long and thin parameres ( Fig. 12 ).

Length 5.7 mm, width (at elytral base) 1.3 mm.

Female differs in simple filiform antennae with elongate narrow antennomeres, compressed and narrow tarsi lacking a comb above 2nd tarsomere in anterior legs, more narrow bases of elytra allowing apical half of pronotum being wider than elytral base, more strongly ovoid and narrowed posteriorly body, hind wings completely reduced.

Length 5.3 mm, width (at elytral base) 1.1 mm.

Distribution. Known only from type locality, Tanzania, Njombe environs ( Fig. 13 ).

Etymology. The species is named after Dr Nikita E. Vikhrev (Zoological Museum of Moscow State University, Moscow) the famous dipterologist, who kindly has collected Malachiidae beetles for a study.

Figures

FIGURES 1–13. Dilatapolochrus vikhrevi Tshernyshev gen. et sp.n., holotype, male, external appearance, dorsal view (1); external appearance, lateral view (2); left antenna (3); left anterior tarsus (4); tibia and tarsus of left anterior leg, dorsal view (5); tibia and tarsus of left anterior leg, lateral view (6); left leg, dorsal view (7); left leg, ventral view (8); pygidium (9); ultimate abdominal ventrite (10); aedeagus, dorsal view (11); tegmen (12); distribution map (13). Scale bar 0.5 mm.