Mistran, Alekseev, Vitalii I. & Bukejs, Andris, 2016

Alekseev, Vitalii I. & Bukejs, Andris, 2016, New fossil genus of Silvanidae (Insecta: Coleoptera) from Baltic amber (Tertiary, Eocene), Zootaxa 4144 (1), pp. 101-108 : 102-103

Mistran gen. nov.

Type species: Mistran ot sp. nov.

Differential diagnosis. Mistran gen. nov. is placed within Silvanidae because of the subparallel body form, the pentamerous tarsi, the closed procoxal cavities, open mesocoxal cavities, and the clubbed 11-segmented antennae. The new fossil genus shows the combination of characters corresponding to the Silvaninae subfamily: posteriorly closed procoxal cavities, loosely clubbed antennae, carinate pronotum and elytra, finely pubescent dorsum, pentamerous tarsi with the fourth segment smallest.

The new genus resembles and is similar in general appearance to the New World Nausibius Lentz, 1857 (head without antennal grooves ventrally, lateral margins of pronotum undulating in form of six rounded teeth, no tarsomeres lobed, antennae robust and weakly clubbed, temples absent), but is distinct from this genus by the combination of following morphological characters: (1) distinctly carinate pronotum and elytra, (2) absence of depression on pronotal base and only slightly flattened dorsum, (3) thickened claws, (4) tarsomere 1 not longer than tarsomere 2, and (5) bases of elytra not raised beside scutellum.

Mistran gen. nov. differs from the extant related silvanine genera by the following morphological characters: from the Australian Austronausibius Halstead, 1980 by the absent temples and rounded antennomere 11 without process; from the Old World Oryzaephilus Ganglbauer, 1899 by the not incrassate tarsomere 3 and absent temples; from the Old World Pseudonausibius Halstead, 1980 by the antennomere 11 without pointed apex and transverse antennomere 8; from the Ethiopian Afronausibius Halstead, 1980 by the absence of ventral antennal grooves, pronotal shape and form of antennae; from the Neotropical Eunausibius Grouvelle, 1912 by the absence of ventral antennal grooves on the head; from the Oriental Acorimus Halstead, 1980 and the Ethiopian Afrocorimus Halstead, 1980 by the dorsal pubescence composed of weakly curved setae and by the pronotal shape.

Mistran gen. nov. can be distinguished from Airaphilus Redtenbacher, 1858 by the carinate and subquadrate pronotum with six weak denticles on each lateral side (longitudinal in shape, with lateral margins finely denticulate or smooth in Airaphilus ), and finer pubescence of dorsal surface (distinctly longer and thicker in Airaphilus ).

Dendrobrontes Kirejtshuk, 2011 differs from Mistran gen. nov. in numerous characters, most notably the long antennae without club (about 1.4 × as long as body). Cryptamorpha Wollaston, 1854 differs from new genus by the bilobed tarsomere 3, the securiform terminal labial palpomere, the longitudinal grooves on the frons, the present scutellary striole and the tuberculate lateral pronotal margins.

Etymology. The name of the new genus is derived from mistran (or mistras), meaning “leader, Grand Master of the Teutonic Order” in the Old Prussian language. The gender is masculine.

Note. The new genus is monotypic, represented by the type species only. Therefore the generic description considerably overlaps that of the species.