Diversity and morphology of Eocene and Oligocene Mordellidae (Coleoptera) Author Batelka, Jan Author Rosová, Kateřina Author Prokop, Jakub text Acta Entomologica Musei Nationalis Pragae 2023 2023-12-30 63 2 451 478 http://dx.doi.org/10.37520/aemnp.2023.027 journal article 10.37520/aemnp.2023.027 1804-6487 10621277 4F6482C1-A2F2-4406-A115-B8E0F205806C Baltistena atronigra sp. nov. ( Figs 9G–K , 10F ) Type material. HOLOTYPE : PřfUK108, obtained from ‘vermiculosis’ – Poland : Baltic amber. Description. Head subglobular, frons continuously convex, posterior edge of eye near posterior margin of head, elytra convex, metacoxae broad, comb formula 5//5/?/?/?, pygidium long. Main characters: Only right antenna almost complete, but poorly visible because of distortion; four basal antennomeres short and cylindrical; antennomere V as long as preceding two, with distal edge distinctly wider; antennomere IX almost cylindrical with apex slightly wider, antennomeres X and XI cylindrical. Maxillary palpomere IV small, malleiform (bean-shaped). Facetes moderatelly sized. Long interfacetal setae present. Form of scutellum indiscernible (dorsal view not available). Basal side of pronotum indiscernible (dorsal view not available), posterior angles of pronotal disc obtuse. Elytra about 3.5× as long as pronotal disc. Protarsomeres cylindrical, straight, length ratios not measurable. Shape of protibia not discernible. Mesotarsomere IV cylindrical, straight. Mesotibia as long as respective tarsus. Metatibia with five long transverse combs. Two subequal tibial spurs inserted on metatibia, but their length not measurable. Metatarsomere I with five long transverse combs, metatarsomeres II with two short combs, tarsomeres III–IV poorly visible. Pygidium 2.5× as long as hypopygium. Metanepisternum partly hidden behind middle leg. Metakatepisternum fully developed, suture between metakatepisternum and metaventrite straight, metacoxal margin distinctly concave ventrally. Pretarsal claws with distinct sharp long teeth. Tip of pygidium with setae similar to those on rest of pygidium. Lengths (in mm): pronotal disc = 0.85, elytra = 3.0, mesotibia = 0.9, metatarsomere I = 0.6, pygidium = 1.3. Etymology. The species name refers to the dull black colour of the body; adjective. Figs 9. A–K – Mordellistenini, Baltic amber.A–F – Baltistena brevispina sp. nov. , holotype, PřFUK95: A – habitus; B – hind leg; C – eye; D – hypopygium; E – middle leg; F – fore leg. G–K – Baltistena atronigra sp. nov. , holotype, PřFUK108: G – habitus; H – eye; I – hind legs; J – hypopygium; K – base of pronotal disc and scutellum. Scale bars: A – 1.0 mm; B – 0.4 mm; C, J – 0.3 mm; D, I – 0.5 mm; E, F – 0.15 mm; G – 0.8 mm; H, K – 0.2 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. Table 2. Comparison of Baltistena atronigra sp. nov. with extant genera of Mordellistenini .

Mordellistenini with truncate pro- and mesotarsomere IV	Prominent generic character(s) of respective genus/subgenus			Difference in Baltistena atronigra n.sp.
Mordellistena (s. str.) Costa, 1854	finely faceted eyes	roughly faceted eyes
Mordellistena ( Pseudomordellina Ermisch, 1952 )	finely faceted eyes	roughly faceted eyes
Mordellistena ( Mordellokoiles Franciscolo,1952 )	finely faceted eyes	roughly faceted eyes
Mordellina (s. str.) Schilsky, 1908	outer metatibial spur absent	both metatibial spurs present
Mordellina ( Pseudomordellistena Ermisch, 1951 )	at least the most distal metatibial comb strongly oblique	long	and	all metatibial combs transverse
Gymnostena Franciscolo, 1950	eyes glabrous	eyes with interfacetal setae
Mordelloxena Franciscolo, 1950	eyes glabrous, pygidium reduced	eyes with interfacetal setae, pygidium developed
Mordellistenula Stchegoleva-Barovskaya, 1930	eyes glabrous, head compressed dorso-ventraly			eyes with interfacetal setae, globular	head	convex,	semi-
Uhligia Horák, 1990	eyes glabrous, head compressed dorso-ventraly			eyes with interfacetal setae, globular	head	convex,	semi-
Mordellochroa Emery, 1876	eyes glabrous	eyes with interfacetal setae
Mordellistenochroa Horák, 1982	eyes glabrous	eyes with interfacetal setae
Tolidostena Ermisch, 1942	eyes glabrous	eyes with interfacetal setae

Differential diagnosis. This species is characterized by truncated pro- and mesotarsomere IV, antennomeres I–IV combined shorter than antennomeres V–VII combined, antennomere IV cylindrical, half the length of antennomere V, antennomere V robust, distinctly broader apically, maxillary palpomere IV small malleiform (bean-shaped), eyes with large facets with long interfacetal setae, posterior angles of pronotal disc obtuse, suture between metakatepisternum and metaventrite straight, metacoxal margin distinctly concave ventrally, combs short and transverse, complete comb formula indiscernible. For its features differing from the 12 extant genera and subgenera with truncated pro- and mesotarsomere IV see Table 2 .