Microscapha kugelanni, Alekseev & Bukejs, 2021

Alekseev, Vitalii Igorevich & Bukejs, Andris, 2021, Fossil Melandryidae (Coleoptera: Tenebrionoidea) from Eocene Baltic amber of the Sambian peninsula: new genus, six new species, new records and key to described taxa, Zootaxa 4965 (1), pp. 142-166 : 150

Microscapha kugelanni sp. nov.

( Figs. 4 , 9C )

Type material. Holotype: No AWI-141 [ CVIA] “* Holotype / Microscapha / kugelanni sp. nov. / Alekseev et Bukejs des. 2021” [red handwritten label]; adult, sex unknown. A complete beetle included in a transparent, yellow amber piece with approximate dimensions of 12 mm × 9 mm and a maximum thickness of 7 mm; preserved without supplementary fixation. Syninclusions are absent.

Type stratum. Baltic amber from Eocene amber-bearing blue Earth layers, mostly Bartonian age is interpreted for the extinct central European resin-producing forests ( Bukejs et al. 2019).

Type locality. Baltic Sea coast, Sambian (Samland) Peninsula, Kaliningrad Region, Russia. Surf zone, 2016 year .

Description. Measurements: body length 1.5 mm, body maximum width 0.81 mm; pronotum length 0.29 mm, pronotum maximum width 0.66 mm; elytra length 1.3 mm, elytra maximum width 0.81 mm.

Body oblong-oval, distinctly convex dorsally and slightly convex ventrally; rufous, unicolorous. Dorsal surface evenly punctured and covered with very fine and decumbent, inconspicuous pubescence.

Head inflexed downwards, only small portion of vertex visible in dorsal view; frons with fine, shallow and almost indistinct punctuation. Compound eyes large, vertical, reniform, almost flat; inner margin emarginated; interocular distance equal to 0.4 times vertical diameter of one eye. Clypeal anterior margin concave. Antennae rather short, 11-segmented, clavate, inserted between and close to inner margin of eyes, extending to base of elytra; scape and pedicel large, subcylindrical, subequal in length; antennomeres 3–5 very short (not distinctly visible in examined specimen); antennomeres 6–7 subquadrate; antennomere 8 slightly elongate; antennomeres 9–11 nearly equal in length, forming elongate spindle-shaped antennal club, nearly as long as antennomeres 1–7 combined, antennomere 11 pointed. Maxillary palpi large, palpomere 4 distinctly dilated apically, slightly longer than wide, with apex truncate.

Pronotum convex, transverse, about 2.3× wider than long, without impressions, widest at base, finely punctate. Lateral margins slightly rounded, gradually narrowed anteriad; lateral carina complete; posterior margin slightly bisinuate; anterior margin arcuate. Anterior angles not pronounced, broadly rounded; posterior angles roundly rectangular. Prohypomera without distinct punctures. Scutellar shield distinct, as long as wide, triangular with rounded lateral sides.

Elytra 1.24× longer than wide, about 3.7× longer than pronotal length, widest in basal half, slightly and gradually narrowed to apex; base nearly as wide as pronotal base; covered with fine, relatively dense irregular punctures. Sutural striae well developed, discernible in posterior four-fifths of elytra. Epipleura narrow, widest at humeri and then gradually narrowing posteriorly. Metaventrite with sublanceolate medial depression in posterior two-thirds of length.

Forelegs short and slender; hind legs longer and most robust. Pro- and mesocoxae oblong, transverse, narrowly separated; metacoxae large, transverse, distinctly wider than metafemora, almost contiguous. Femora flattened; metafemora strongly widened, about 1.5× wider than mesofemora. Pro- and mesotibiae almost straight, with subparallel lateral sides; metatibiae narrowly triangular, about 2.4× longer than wide at apex; metatibiae with two long serrate spurs, subequal in length, about 0.85× longer than metatarsomere 1. Tarsal formula 5-5-4. Protarsus subequal in length to protibia, mesotarsus about 1.4× longer than mesotibia, metatarsus about 2.2× longer than metatibia. Ratio of relative lengths of mesotarsomeres 1–5 = 6:3:2:3:3; ratio of relative lengths of metatarsomeres 1–4 = 13:5:5:6. Pretarsal claws simple, small.

Abdomen with five visible ventrites; finely and densely punctured, distance between punctures equal to 0.5– 1.5× diameter of one puncture; ventrite 5 with very shallowly emarginated apical margin; ratio of relative lengths of ventrites 1–5 = 10:10:7:7:10 (medially).

Remark. Metathoracic wings hidden. Forelegs, middle antennomeres and palpomeres are visible in contours only, perhaps due to preservation state of the specimen.

Etymology. The epithet of this new species is patronymic. The species is named after Johann Gottlieb Kugelann (1753–1815), born in Königsberg, an entomologist who worked on Coleoptera of the region.

Differential diagnosis. Microscapha kugelanni sp. nov. differs from the morphologically similar extinct M. andrzeji Bukejs et Alekseev, 2015 from Baltic amber by shorter and wider body, about 1.9× longer than wide (in contrast to about 2.2× longer than wide in M. andrzeji ); in smaller body length (1.7 mm in M. andrzeji ); more rounded sides of scutellar shield (straight in M. andrzeji ); and anteriorly incomplete sutural stria.

Figures

FIGURE 4. Microscapha kugelanni sp. nov., holotype, No AWI-141 [CVIA]: A—habitus, right lateral view; B—habitus, dorsal view; C—habitus, ventral view; D—details of forebody, ventro-lateral view. Scale bars represent 1.0 mm.

FIGURE 9. Reconstructions of new fossil Melandryidae from Baltic amber:A—Electroxylita chronographica gen. et sp. nov.; B—Phloiotrya inmarinata sp. nov.; C—Microscapha kugelanni sp. nov.; D—Madelinia capillata sp. nov.; E—Symphora glaesonauta sp. nov. Not reproduced to the same scale, punctuation and setation are omitted.