Nalassus (Nalassus) becvari Nabozhenko & Keskin, 2020

Nabozhenko, Maxim, Keskin, Bekir & Papadopoulou, Anna, 2020, Two new species and new records of darkling beetles of the tribe Helopini from Turkey and Cyprus (Coleoptera: Tenebrionidae), Acta Entomologica Musei Nationalis Pragae 60 (2), pp. 411-417 : 415

Nalassus (Nalassus) becvari Nabozhenko & Keskin , sp. nov.

( Figs 8–12 )

Type material. HοΓοτΥΡΕ: ♁ ( NMPC), labelled: ‘Anatol. or. / ELAZIG // Coll. Kadlec’. The holotype was previously deposited in SBCP, but Stanislav Bečvář kindly agreed to transfer it to NMPC.

Description. Body small (length 6.4 mm, width 2.5 mm), slender, brown, shiny, moderately convex.

Head widest at eye level, 1.52 times as wide as interocular space of frons, covered with recumbent setae on vertex, genae and near eyes. Eyes convex, transversely elongate, bean-shaped. Epistomal anterior margin straight. Outer margin of genae angulate, strongly rounded in basal third and straight in apical two thirds. Lateral margin of head without emargination between genae and epistoma. Punctation of head coarse and dense, puncture diameter 1.5–2.0 times as long as interpunctural distance; punctures deep, round. Ventral aspect of eye with a weak posterior ventral impression (not groove). Head ventrally with very coarse punctation and subrecumbent pubescence. Apical maxillary palpomeres strongly widened and flattened, securiform, transverse, with rounded anterior margin.Antennae with strongly thickened oval antennomeres 3–8. Ratio of length/width of antennomeres 2–11: 0.7/0.6, 1.6/0.8, 1.2/0.9. 1.2/0.9, 1.3/1, 1.2/1, 1.3/1, 1/1, 1/1, 1.2/0.9.

Prothorax. Pronotum transverse (1.32 times as wide as long), widest slightly before middle, 1.54 times as wide as head. Lateral margins weakly rounded, slightly sinuate near posterior angles; anterior margin weakly widely emarginate; base weakly rounded, with short emargination along scutellum.Angles narrowly rounded at apex, anterior ones rectangular, posterior ones weakly obtuse. Lateral margins and base narrowly beaded, anterior margin beaded only near angles. Disc weakly evenly convex, sides narrowly flattened, punctation slightly finer and sparser than on head, sparser in middle and near margins (puncture diameter 2–4 times as short as interpunctural distance) and denser on sides (puncture diameter subequal or little wider than interpunctural distance). Prosternum with coarse irregular wrinkles (but punctured near procoxae) and erected setae. Prosternal process very weakly convex. Prothoracic hypomera strongly flattened along outer margin, longitudinally wrinkled and vested with long recumbent setae in anterior and basal parts.

Pterothorax. Elytra elongate, oval, widest in middle (1.58 times as long as wide), 1.81 times as wide as head, 1.17 times as wide and 2.46 times as long as pronotum. Strial punctures elongate, merged in interrupted grooves. Interstriae flat, with coarse and sparse punctation (punctures slightly smaller than in striae). Eighth interval not more convex than others and apically connected with second interval. Lateral deflected margin of elytra visible dorsally. Epipleura strongly depressed along whole length, not reaching sutural angle (ended slightly before apex). Mesoventrite with coarse and dense punctation of round punctures and recumbent pubescence. Wings reduced, small. Metaventrite and metepisterna with coarse, not dense punctation (puncture diameter subequal to interpunctural distance) and short recumbent setae. Legs slender; protrochanters with 3 long setae, other trochanters with 1 long seta; femora with erected setae at base of inner side; tibiae straight, margins around apex with long setae (not spines); tarsomeres elongate, not widened, densely pubescent on plantar side.

Abdomen. Abdominal ventrites with coarse, moderately dense punctation (puncture diameter subequal to interpunctural distance) of round punctures and very short recumbent setae, ventrite 1 without brush of long setae; ventrite 5 more finely punctured, with beaded margin. Aedeagus ‘nalassoid’, weakly sclerotized, with laterally flattened keel at apex ( Figs 9–10 ). Male inner sternite VIII and spiculum gastrale typical for Nalassus ( Figs 11–12 ).

Differential diagnosis. With strongly depressed, epipleura almost reaching apex, the species is externally similar to Nalassus kaszabi Nabozhenko, 2001 from Van Province, which was transferred to the subgenus Helopondrus Reitter, 1922 on the basis of preliminary analysis of COI markers (KΕඌΚΙΝ et al. 2017b). On the other hand, males of N. kaszabi are unknown, and we cannot support our molecular data by the structure of male genitalia. Nalassus becvari sp. nov. differs from N. kaszabi in narrowly flattened sides along lateral margins of pronotum and epipleura not reaching elytral sutural angles. The new species differs from all other Turkish species of Nalassus s. str. in the ventral aspect of eye, which bears a weak posterior ventral impression (rather than a distinct groove of other species). This new species can be distinguished from other Turkish Nalassus s. str. using the key below.

Etymology. The species is named in honour of our colleague, Stanislav Bečvář, who transferred to us many interesting darkling beetles for study. The name is a noun in singular genitive case.

Figures

Figs 8–12. Nalassus becvari sp. nov., holotype. 8 – male habitus; 9 – aedeagus, ventral view; 10 – aedeagus, lateral view; 11 – male inner sternite VIII; 12 – spiculum gastrale, ventral view. Scale bars = 1 mm.