Palaeostena eocenica ( Kubisz, 2003 ) Batelka & Rosová & Prokop, 2023

Batelka, Jan, Rosová, Kateřina & Prokop, Jakub, 2023, Diversity and morphology of Eocene and Oligocene Mordellidae (Coleoptera), Acta Entomologica Musei Nationalis Pragae 63 (2), pp. 451-478 : 458

Palaeostena eocenica ( Kubisz, 2003) comb. nov.

( Figs 2A–C , 10B )

Falsomordellistena (Palaeostena) eocenica Kubisz, 2003: 186 . Holotype:

J, Baltic amber.

Material examined. One specimen, PřfUK107, obtained from Jonas Damzen (original number JDC 8742):? Rovno amber. The specimen conforms with the description and figures of P. eocenica and is thus considered to be conspecific. It represents the first possible record of this species from Rovno amber.

Comments on identification. The author compared this species with extant members of Falsomordellistena because of the similar shape of their antennomeres. However, antennae in Mordellidae are often similar in different genera (see below for an example of a different diagnosis of Baltistena concava sp. nov.). In addition, in males of species of Falsomordellistena antennomeres V–X vary greatly in shape (from feebly serrate to filiform) and are usually 2× as long as wide or longer (e.g., NOMURA 1967, 1975), while in Palaeostena eocenica they are only ‘one half longer than wide’, which must be considered a difference rather than a similarity.

KUBISZ (2003) also lists several characters of P. eocenica , in which this species should differ from all extant Falsomordellistena species: eyes without interfacetal setae; peculiar shape of maxillary palpomere IV (surprisingly, its length is compared with the length of basal antennomeres, not palpomeres); asymmetry of metatibial spurs; absence of body pubescence; and body size. Only the last three of these differences are included in the diagnosis of this species, as according to the author, they delimit P. eocenica from all known species of Falsomordellistena . In summary, KUBISZ (2003) states that P. eocenica differs from extant species of Falsomordellistena in at least five characters usually used for delimiting genera and therefore its inclusion into this extant genus would invalidate the generic diagnosis.

Accepting the validity of this species and the fact that its generic assignment to Falsomordellistena is not supported by the given diagnosis, the subgenus Palaeostena is here raised to generic status.

Figures

Figs 2. A–G – Mordellistenini.A–C – Palaeostena eocenica Kubisz, 2003, PřfUK107, Rovno amber:A – habitus; B – head and antenna; C – mesotarsus with smooth pretarsal claws (black arrow) and protarsus with emarginated tarsomere IV (white arrow). D–G – Baltistena amplicollis (Ermisch, 1941), holotype, Baltic amber: D – habitus; E – hind leg; F – head ventrally; G – middle leg with emarginated tarsomere IV. Scale bars: A, D – 0.5 mm; B, C, G – 0.2 mm; E, F – 0.3 mm.

Figs 10. A–F – Metakatepisternum: A – Baltimorda, undescribed species A, PřfUK71. B – Palaeostena eocenica (Kubisz, 2003), PřfUK107. C – Baltistena hoffeinsorum sp. nov., holotype, PřFUK92. D – Baltistena concava sp. nov., holotype, PřFUK93. E – Baltistena brevispina sp. nov., holotype, PřFUK95. F – Baltistena atronigra sp. nov., holotype, PřFUK108. Scale bars: 0.2 mm.