Baltistena korschefskyi (Ermisch, 1941) 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 : 459

Baltistena korschefskyi (Ermisch, 1941) comb. nov.

( Figs 3D–J )

Mordellistena korschefskyi Ermisch, 1941a: 180 . Syntypes: 3 specimens,

Baltic amber.

Type material examined. LECTOTYPE (here designated) ( SDEI):, ‘ MORDELLISTENA [p] / Korschefskyi [hw] / det. Ermisch 194 [p] i [hw, sic; white label glued on bigger white label] // TYPE [p; in black frame, red label glued on the bigger white label] // SDEI Müncheberg / SDEI- -Amb-000639 [p; yellowish label] ’. PARALECTOTYPES: 2 spec. ( SDEI), ‘ MORDELLISTENA [p] / Korschefskyi [hw] / det. Ermisch 194 [p] i [hw, sic; white label glued on bigger white label] // Cotype [p; in black frame] Cotype [p; in black frame; white label glued on the bigger white label] // SDEI Müncheberg / SDEI-Amb-000635 [p; yellowish label]’.

Comments on identification. According to ERMISCH (1941a), all three type specimens must be considered syntypes because he explicitly noted ‘Es sind drei Exemplare vorhanden (Sammlung D.E.I.) zwei davon stark getrübt.’ The terms ‘type’ and ‘cotype’ have been used only at the labels of respective specimens. Due to the uncertain conspecificity of the three syntypes (see below), the lectotype is designated to preserve stability of the nomenclature of this species, according to the Article 74.7.3 of the Zoological Code ( ICZN 1999).

The specimen SDEI-Amb-000639 is designated here as the lectotype because 1) it is complete and very well preserved, 2) Ermisch labelled this specimen as a ‘type’ and both specimens of 635 as ‘cotype’ and 3) Ermisch chose this specimen for his plate VII (fig. 6) as the only representative of this species.

Both pro- and mesotarsomere IV of the lectotype are distinctly broader and shallowly emarginated so it cannot be attributed to Mordellistena . To distinguish this species from other Eocene Mordellistenini see the key below. Because of the uncertain generic identity of this species, it is transferred here into Baltistena new collective group.

The micro-CT scan revealed that one of the paralectotypes SDEI-Amb-000635 ( Figs 4A,B ) has a preapical comb only on the metatibia. The specimen is therefore a member of Mordellini , not Mordellistenini . Subsequent mismatch with Ermisch’s ‘ Mordella sp. ’ is expected (see above). Malleiform maxillary palpomere IV differs from triangular palpomere IV of Mordella spp.

It is likely that the second specimen SDEI-Amb-000635 ( Figs 4C–G ) is not conspecific with the lectotype because in the lectotype the metatarsomere I is about 0.8× as long as metatibia, whereas in the cotype 635 it is only 0.6× as long as the metatibia. In both specimens, the angles of the combs differ. At least protarsomere IV of the Mordellistenini specimen SDEI-Amb-000635 is deeply dilated so it cannot be attributed to Mordellistena .

Figures

Figs 3. A–J – Mordellistenini, Baltic amber. A–C – Baltistena antiqua (Ermisch, 1941), holotype: A – thorax ventrally. B, C – hind legs. D–J – Baltistena korschefskyi (Ermisch, 1941), SDEI-Amb-000639, lectotype: D, E – habitus; F – head and thorax anteroventrally; G – hind legs; H – maxillary palpomeres IV (black arrows); I – maxillary palpomere IV and antennomeres I–IV; J – pronotal disc dorsally. Scale bars:A, B, G – 0.3 mm; C, H – 0.2 mm; D – 1 mm; E, F – 0.5 mm; I – 0.1 mm.

Figs 4. A, B – Mordellini, Baltimorda sp., SDEI-Amb-000635, head and thorax ventrally including legs. C–G – Mordellistenini, Baltistena sp., SDEI- Amb-000635: C – habitus. D – hind margin of pronotal disc and elytra. E, F – hind legs. G – fore leg. Scale bars:A – 0.4 mm; B – 0.3 mm; C – 0.5 mm.