Baltimorda

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 : 455

Baltimorda ?undescribed species A

( Figs 1C–F , 10A )

Material examined. One specimen, PřfUK71, obtained from Jonas Damzen (original number JDC 9160): Baltic amber.

Description. Body of Mordella - type, cuticle shiny, head subglobular, frons continuously convex, posterior edge of eye near posterior margin of head, elytra convex, metacoxa broad, pygidium long. Main characters: All eleven antennomeres almost equal in length, antennomeres I and II robust, shiny, cylindrical, antennomere III narrow, cylindrical, antennomeres IV–VIII subserrate, slightly flattened, antennomeres IX–XI subcylindrical. Two maxillary palpomeres visible, shape indiscernible. Eyes elliptical, with about 18 facets across their widest part. Eyes glabrous, interfacetal setae absent. Form of scutellum indiscernible. Postero-lateral edges of pronotal disc at right angle. Elytra 3.2× as long as pronotal disc. All protarsomeres slender and cylindrical. Protibia narrow, about 1.5× as long as protarsus. Mesotarsomere IV cylindrical, slightly wider apically, 0.6× as long as tarsomeres III and V. Mesotibia 1.1× as long as respective tarsus. Metatibia with preapical comb parallel with apical setae and with fine dorsolateral ridge along whole length of tibia. Outer tibial spur on metatibia as long as half of metatarsomere I. Metatarsus without combs or ridges. Pygidium 2.6× as long as hypopygium. Anterior edge of metanepisternum 2× as long as its posterior edge, ventral edge 4× as long as posterior edge. Metakatepisternum present, but only dorsal part visible. Pretarsal claws simple, without visible teeth. Tip of pygidium with few dark acute setae.

Lengths (in mm): pronotal disc = 0.75, elytra = 2.56, mesotibia = 0.7, metatarsomere I = 0.5, pygidium = 1.1.

Differential diagnosis. Until there is a detailed investigation of all Baltic Mordellini based on characters other than ridges on the posterior legs, the identity of Baltimorda ?undescribed species A will remain uncertain. This specimen has a fine dorsolateral ridge along the whole length of the metatibia, as is the case in Baltimorda scheelei , B. succinea and B. friedrichi , but the presence or absence of ridges on tarsomeres cannot be verified with the material at hand. In its habitus it is more similar to B. scheelei than to the other two described species. The dorsolateral ridge on the metatibia and sometimes also metatarsus is present in many extant Mordellini genera (see also Differential diagnoses above) and the presence or absence of this structure is no longer sufficient for the identification and placement of Baltic Mordellini .

Figures

Figs 1. Mordellidae, Baltic amber.A – Baltistena sp., SDEI-Amb-000644, hind leg. B – Baltimorda scheelei (Ermisch, 1941), holotype, hind leg. C–F – Baltimorda, undescribed speciesA, PřfUK71: C – habitus; D – head and thorax; E – hind leg (black arrows marking fine dorsolateral ridge); F – pretarsal claws. G–I – Baltimorda, undescribed species B, PřfUK94: G – habitus; H – hind legs; I – metatarsus. Scale bars: A, E, H, I – 0.2 mm; B, D, – 0.3 mm; C, G – 0.5 mm; F – 0.05 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.