Nalassus Mulsant, 1854

Nabozhenko, Maxim & Ando, Kiyoshi, 2018, Subtribal, Generic And Subgeneric Composition Of Darkling Beetles Of The Tribe Helopini (Coleoptera: Tenebrionidae) In The Eastern Palaearctic Region, Acta Zoologica Academiae Scientiarum Hungaricae 64 (4), pp. 277-327 : 293-295

Nalassus Mulsant, 1854

( Figs 7–16 )

Type species: Helops (Nalassus) dryadophilus Mulsant, 1854, by subsequent designation ( Nabozhenko, 2001).

General morphology of adults. Body medial in size (length 5–12 mm), brown or rarely black, usually shiny, rarely with metallic luster, but sometimes dull, moderately flattened. Head with posterior grooves beginning at lower aspect of eyes. This character is, sometimes, not clear and head with posterior longitudinal depression instead of the grooves. East Asian species mainly without these grooves. Eyes moderately large or small (subgenus Caucasonotus Nabozhenko, 2001 ), not strongly transverse. Antennae of male often with weakly or strongly thickened in each antennomere, rarely (in Japanese and Taiwanese species) male and female antennomeres not thickened. Anterior margin of frontoclypeus straight (excluding deeply emarginate in N. melchiades ( REITTER, 1922)). v – vagina, s – spermatheca, o – oviduct)

Pronotum usually weakly convex. Prothoracic hypomera with longitudinal or irregular ( Caucasonotus ) wrinkles. Prosternum punctured, sometimes with smooth irregular wrinkles before procoxae. Prosternal process weakly convex, not projected apically, without teeth. Each elytron devoid of humeral callosity, with clear striae; punctures in striae normally confluent or connected (by furrow) with each other, often free from each other; interstriae with simple coeloconic sensilla, but without tubercles, eighth interstria apically more convex than other ones, connected with elytral margin; dorsal epipleural carina reaching eighth interval at apex; epipleura not reaching elytral apex and finished at level of abdominal ventrites 4 and 5. Hind wings completely developed or absent. The most of species are flightless, but some Japanese and probably Taiwanese species can fly (observations of junior author, K. A). Mesoventrite slightly depressed at middle. Metaventrite transverse, glabrous or rarely densely pubescent (subgenus Nipponalassus subgen. n.). Male abdominal ventrites 1, 2 and sometimes 5 often with dense or sparse ( Caucasonotus ) hair brushes. Legs moderately slender, tibiae simple, without teeth, not flattened nor curved. Male tarsi not widened or protarsomeres II–III slightly widened. Trochanters with single long seta, rarely ( Nipponalassus ) with dense hair brush.

Aedeagus ‘nalassoid’ ( Figs 7A–D, E–H ) (subgenera Nalassus , Caucasonotus , Nipponalassus in part) or ‘cylindrinotoid’ ( Fig. 7I, J ) (subgenus Helopondrus Reitter, 1922 , one species of Nipponalassus , one species of the nominotypical subgenus).

Female genital tubes ( Fig. 7M ). Spermatheca consists of only one non-branched tube (the most of all subgenera) or the tube with several very short branches at the base. Accessory gland short, a little longer than spermatheca or subequal to spermathecal length. Basal duct of spermatheca present or short.

Comments. The genus is divided into four subgenera: nominotypical, Helopondrus , Caucasonotus and Nipponalassus subgen. n. The subgenus Helopocerodes Reitter, 1922 was recently placed in the junior synonym of the nominotypical subgenus ( KESKIN et al. 2017). Species of the subgenus Helopondrus have ‘cylindrinotoid’ male genitalia and female genital tubes but clearly belong to the genus Nalassus on larval morphology ( NABOZHENKO & ARTOKHIN 2017).

Composition. The genus contains recent species and subspecies: ten species and one subspecies in the Pacific Palaearctic region ( China, Japan, Korean Peninsula, Taiwan, and the Russian Far East), three species in the Nearctic region (NABOZHENKO et al. 2016) and 68 species and subspecies in the Central and Western Palaearctic.

Figures

Fig. 7. The genus Nalassus, genital structure: N. (s. str.) pilushenmuus (A–D), N. (s. str.) zoltani (E–H), N. (Nipponalassus) andoi (I–M), N. (Nipponalassus) lewisi (O–R): A, E, I, O = aedeagus, ventral view, B, F, J, P = aedeagus, lateral view, C, G, K, Q = male inner sternite VIII, D, H, L, R = gastral spicula, M = female genital tubes (ag – accessory gland of spermatheca,

Fig. 8. Nalassus (s. str.) brunneus brunneus, details of structure: A = head and prothorax, ventral view, B = head, ventral view (arrow shows weakly developed posterior grooves beginning at lower aspect of eyes), C = prosternum, D = prosternal process, procoxae and

Fig. 9. Nalassus brunneus konoi, holotype, female: A = habitus, B = labels, C = protibia, D = mesotibia

Fig. 10. Nalassus (s. str.) akitai, holotype and paratype: A = male, holotype, habitus, B = fe-

Fig. 11. Nalassus (s. str.) kawabatai, holotype and paratype. A = male, holotype, habitus, B = aedeagus, dorsal view, C = female paratype, habitus, D = male protibia, E = male mesotibia, F = male metatibia, G = male profemur, inner side, H = male prothorax, ventral view, I =

Fig. 12. Nalassus (s. str.) from Taiwan, habitus. A = N. formosanus, female, B = N. zoltani, male, C = N. pilushenmuus, male

Fig. 13. Nalassus (Nipponalassus) andoi, holotype and paratype. A = male, holotype, habitus, B = female paratype, habitus, C = male fore leg, dorsal margin, D = male profemur, inner side, E = aedeagus, dorsal view, F = prothorax, ventral view, G = abdominal ventrite 5, H = labels of the holotype

Fig. 14. Nalassus (Nipponalassus) andoi, details of structure. A = Head, ventral view, B = prothorax and base of fore legs, ventral side, C = male meso- and metaventrite, middle legs

Fig. 15. Nalassus (Nipponalassus) lewisi, holotype and paratype.A = male, holotype, habitus, B = female paratype, habitus, C = labels of the holotype, D = aedeagus, dorsal view

Fig. 16. Nalassus (Nipponalassus) lewisi (A, C–F) and N. (Nipponalassus) andoi (B), details of structure: A = head, ventral view, B = male abdominal ventrite 5, C = male meso- and metaventrite, middle legs basally, D = male abdominal ventrites, E = male profemur, inner side, F = male profemur dorsally