Baltistena hoffeinsorum, 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 : 468

Baltistena hoffeinsorum sp. nov.

( Figs 7E–I , 10C )

Type material. HOLOTYPE: PřfUK92, obtained from Jonas Damzen (original number JDC8781 ): Baltic amber.

Description. Head subglobular, frons continuously convex, posterior edge of eye near posterior margin of head, elytra convex, metacoxae broad, comb formula 6//5/3/0/0, pygidium long. Main characters: Antenna 3.25× as long as width of eye, basal antennomere robust, flagellomeres cylindrical, antennomere IX and X 3.0× as long as wide apically, antennomere XI 2.3× as long as wide. Structure of maxillary palpi, notably ultimate palpomere, indiscernible. Eyes rather coarsely facetted. Interfacetal setae present, distinctly shorter than diameter of facets. Form of scutellum indiscernible (dorsal view not available). Basal side of pronotum indiscernible (dorsal view not available). Elytra 2.7× as long as pronotal disc. Protarsomere I about 1.1× as long as remaining tarsomeres combined, tarsomere IV deeply dilated. Protibia seems to be shallowly curved in lateral view. Mesotarsomere IV deeply dilated. Mesotibia about 1.3× as long as respective tarsus. Metatibia with six very short transverse combs. Metatibia with two subequally long spurs, about as long as 3/4 of metatarsomere I. Metatarsomere I with five short transverse combs, metatarsomere II with three short combs, tarsomeres III and IV without combs. Pygidium 3.1× as long as hypopygium. Anterior edge of metanepisternum 2.0× as long as its posterior edge, ventral edge 4.0× as long as its posterior edge. Metakatepisternum fully developed; suture between metakatepisternum and metaventrite straight, metacoxal margin distinctly concave ventrally. Pretarsal claws distinctly dentate. Tip of pygidium with setae similar to those on remaining parts of pygidium.

Lengths (in mm): pronotal disc = 1.1, elytra = 3.0, mesotibia = 0.8, metatarsomere I = 0.6, pygidium = 1.4.

Etymology. The species name is given in honour of Christel and Hans Werner Hoffeins, outstanding German paleoentomologists; noun in apposition.

Differential diagnosis. Eyes finely faceted with short setae, penultimate pro- and mesotarsomeres deeply dilated, antennomeres long, narrow and cylindrical, antennomeres I– III 2× as long as wide, antennomeres IV–VII indiscernible, antennomeres VIII–X 3.5× as long as wide, antennomere XI 5× as long as wide. This species can be distinguished from other Eocene species using the key below. More characters, notably of the palpomeres and genitalia, need to be observed for a better comparison with extant genera with deeply dilated penultimate pro- and mesotarsomeres.

Figures

Figs 7. A–I – Mordellistenini, Baltic amber. A–D – Baltistena longistrigata sp. nov., holotype, PřFUK69: A – habitus; B – hypopygium; C – hind leg; D – head and pronotum laterally. E–I – Baltistena hoffeinsorum sp. nov., holotype, PřFUK92: E – habitus; F – hind legs; G – metatarsomere IV and serrate pretarsal claws; H – hypopygium; I – eye. Scale bars: A, F – 0.5 mm; B – 0.15 mm; C, D, H – 0.2 mm; E – 0.8 mm; G – 0.05 mm; I – 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.