Palaeobasanus neli, Nabozhenko & Kirejtshuk, 2020

Nabozhenko, Maxim V. & Kirejtshuk, Alexander G., 2020, The Oldest Tenebrionidae (Coleoptera) Of The Subfamily Diaperinae And The Tribe Scaphidemini From The Paleocene Of Menat (France), Acta Zoologica Academiae Scientiarum Hungaricae 66 (1), pp. 23-33 : 27-28

Palaeobasanus neli sp. n.

( Figs 1–2 )

Type material: holotype MNT 06 3415 (sex unknown)

Description. Body length about 7.5 mm. Head about half as wide as pronotum; mentum with longitudinal median elevation ( Fig 1D ); Head underside with dense and coarse subcircular punctures around throat emargination; other ventral sclerites with undulate transverse wrinkle-like foveae ( Fig. 1D ); gula short, with weakly rounded margins. Antennomeres 4-7 elongate, with dense simple trichoid sensillae ( Fig. 1C ), without sensory complexes; apical antennomeres (beginning from antennomere 8) subquadrate and short.

Pronotum transverse ( Figs 1A, B, D ; 2A ), nearly 3.5 times as wide as long, widest at base; lateral margins and base evenly weakly arcuate; anterior margin shallowly emarginated; lateral margins strongly beaded ( Fig. 1B, D ); anterior angles subacute, weakly projected; posterior angles subacute but rounded at tip.

Elytra at base little wider than base of pronotum, with eight striae and scutellary striola; humeri rounded, not projected; striae deep, bearing a row of circular punctures at bottom ( Figs 1A , 2A ). Mesoventrite with median elevation and transverse wrinkles, strongly depressed before mesocoxae; mesocoxae transversely suboval; metaventrite transverse (2.6 times as wide as long, with median impressed furrow in basal part and groove along metacoxal cavities; intercoxal process of metaventrite rounded and beaded.

Legs moderately long; femora not strongly protruded beyond body lateral edges; tibiae straight; metatarsi with long metatarsomeres 1 and 4; metatarsomere 4 the longest (longer than metatarsomeres 2 and 3 combined).

Etymology. The species is named in honor of Prof. André Nel (MNHN), the famous paleoentomologist, who made a great contribution to the study of the paleofauna of Menat.

Comparative diagnosis is the same as for the genus Palaeobasanus gen. n.

Figures

Fig. 1. Palaeobasanus neli gen. et sp. n. holotype, Paleocene of Menat (France) imprint: A = imprint, general view, optic microscope, B = the same, SEM, C = head, optic microscope, D = prosternum and head, SEM, m = mentum, pcx = procoxae

Fig. 2. Palaeobasanus neli gen. et sp. n. holotype, Paleocene of Menat (France), details of the structure: A = reconstruction, B = right half of pterothorax, msvt = mesoventrite, msept =mesepisternum, msem = mesepimeron, tr = trochantine, mtept = metaepisternum, mtvt = metaventrite, mcox = mesocoxa