Madelinia capillata, 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 : 151-154

Madelinia capillata sp. nov.

( Figs. 5 , 8C , 9D )

Type material. Holotype: No 6708 [ MAIG] (ex. coll. Jonas Damzen JDC 8368), “ Holotype / Madelinia capillata sp. nov. / Alekseev et Bukejs des. 2021” [red printed label]; adult, male. An almost complete beetle (right antenna missing) with partially exposed metathoracic wings and apical portion of aedeagus; included in a transparent, yellow amber piece with approximate dimensions of 21 mm × 12 mm and a maximum thickness of 8 mm; preserved without supplementary fixation. Organic syninclusions: one Nematocera ( Diptera ) specimen and some small stellate fagacean trichomes.

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. Yantarny settlement (formerly Palmnicken), Sambian (Samland) Peninsula, Kaliningrad Region, Russia .

Description. Measurements: body length about 4.2 mm, body maximum width 1.2 mm; pronotum length 0.9 mm, pronotum maximum width 1.1 mm; elytra length 3.2 mm, elytra maximum width 1.2 mm.

Body oblong, flattened dorsally and slightly convex ventrally; brown with antennae (except scape) and legs paler. Body pubescence consists of: (1) fine, rather dense, almost recumbent setation dorsally and ventrally, and (2) slightly longer, sparse and erect setae on head, pronotum and elytra.

Head prognathous, well visible in dorsal view, densely covered with fine punctuation; frons flat; vertex slightly convex; genae short, about 0.3× as long as horizontal diameter of one eye. Fronto-clypeal suture apparently present but poorly discernible. Compound eyes rather large, entire, slightly prominent, oval, vertical diameter about 1.5× longer than horizontal diameter; facets distinct and fine, without intrafacetal setae; interocular distance at upper margin of eyes about 0.75× as vertical diameter of one eye. Maxillary palpi rather long, about 0.4× as long as antenna; with 4 palpomeres: palpomere 1 minute, triangular, nearly as long as wide, palpomere 2 elongate triangular, with slightly oblique apical margin, about 1.8× longer than maximum wide, palpomere 3 shorter than palpomere 2 (poorly visible in studied specimen), palpomere 4 large, cultriform, about 3.3× longer than wide; ratio of relative lengths of maxillary palpomeres 1–4 = to 5:14:?:30. Antennae with 11 antennomeres, filiform, inserted between and close to inner margin of eyes, pubescent, rather short, reaching posteriorly to humeri; scape cylindrical, 1.8× longer than wide; pedicle subcylindrical; antennomeres 3–10 conical, elongate, subequal in size, about 1.7–2.1× longer than maximum wide; antennomere 11 narrowly ovoid with pointed apex, 2.2× longer than maximum wide, and about 1.3× longer than antennomere 10; ratio of relative lengths of antennomeres 1–11 = 16:15:17:17:17:17:1 7:17:17:17:22.

Pronotum slightly transverse, 1.2× wider than long, widest at middle, base closely associated with elytral base; densely covered with small punctuation, distance between punctures equal to 0.5–1.0× diameter of one puncture; disc convex, with shallow, rounded impression laterally. Anterior pronotal margin straight (in dorsal view); posterior margin slightly narrower than elytral anterior margin, weakly bisinuated, markedly protruding medially, distinctly margined; lateral margins rounded, slightly narrowed anteriad and more distinct posteriad. Lateral pronotal carina present, distinct in basal one-third of pronotal length. Anterior pronotal angles rounded; posterior angles acute, slightly protruding posteriad. Basal impressions triangular with widely rounded apex, deep, reaching about one-fourth of pronotal length. Prohypomera convex, densely covered with small punctuation. Scutellar shield rather large, subpentagonal, slightly elongate, about 1.1× longer than wide.

Elytra narrowly ovate, elongate, about 2.7× longer than wide, widest in posterior one-third, almost parallelsided in anterior two-third, gradually narrowed in posterior one-third; humeri distinct, prominent; elytral apices rounded separately; elytral punctuation irregular, small and dense, distance between punctures lesser than diameter of one puncture, punctuation slightly sparser and smoother in posterior portion. Hind wings present, macropterous. Epipleura narrow, widest basally and gradually narrowed posteriad, reaching posterior margin of abdominal ventrite 1. Metepisternum rather wide, slightly dilated anteriorly, with subparallel lateral sides, about 4.7× longer than maximum wide, densely covered with small punctuation. Metaventrite with convex disc, densely covered with small punctures, distance between punctures lesser than diameter of one puncture.

Legs slender, long, with dense, fine punctuation. Procoxae contiguous, conical; mesocoxae roundish, apparently very narrowly separated; metacoxae elongate oval, transverse, narrowly separated. Femora clavate, flattened. Tibiae subcylindrical, almost straight, slightly dilated apically, subequal in length to femora, with two short spurs of equal length and fringe of spinulae apically; metatibial spurs about 0.5× as long as metatibial width at apex. Tarsi long, metatarsus nearly as long as metatibia; tarsal formula 5-5-4; penultimate tarsomere of all legs deeply bilobed; metatarsomere 1 not shorter than one-half of metatibia, ratio of relative lengths of metatarsomeres 1–4 = 20:10:5:7. Pretarsal claws simple, strongly divergent, symmetrical.

Abdomen with five visible ventrites, densely covered with small punctuation, distance between punctures lesser than diameter of one puncture; ventrite 5 with rounded apical margin; ratio of relative lengths of ventrites 1–5 = 20:17:15:11:12 (medially).

Apical portion of aedeagus as in Fig. 8C .

Etymology The epithet of this new species (Latin adjective capillatus, meaning “hairy, long-haired, old-fashioned”) refers to its long, conspicuous dorsal pubescence.

Differential diagnosis. Madelinia capillata sp. nov. differs from M. gedanoposita Alekseev et Pankowski, 2020 in: (1) shape of pronotum, lateral pronotal margins rounded, narrowed anteriad and posteriad; (2) distinctly longer and conspicuous pubescence of the dorsum; (3) slightly elongate scutellar shield (transverse in M. gedanoposita ); (4) comparatively longer metatarsomere 2 (the ratio of metatarsomeres 1–2 in the new species consists 2:1, whereas the ratio in M. gedanoposita consists 4:1); and (5) smaller body (4.2 mm in contrast to 5.8 mm in M. gedanoposita ).

Note. The shape of pronotum and the body size can vary within certain limits in extant representatives of the tribe. The main diagnostic characters for species limitation within the extinct genus Madelinia is considered the pubescence, the shape of scutellar shield and the comparative lenghts of metatarsomeres 1–2.

Figures

FIGURE 5. Madelinia capillata sp. nov., holotype, No 6708 [MAIG], habitus:A—dorsal view; B—left lateral view. Scale bars represent 1.0 mm.

FIGURE 8. Apical portion of aedeagus in ventral view: A—Electroxylita chronographica gen. et sp. nov.; B—Phloiotrya inmarinata sp. nov.; C—Madelinia capillata sp. nov.; D—Symphora pollocki sp. nov. Not reproduced to the same scale.

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.