Amelyris ( Asymelyris ) paucidentatus Tshernyshev, Alekseev, Bukejs, Vasilenko, Legalov & Perkovsky

Tshernyshev, Sergei E., Alekseev, Vitalii, Bukejs, Andris, Vasilenko, Dmitry V., Legalov, Andrej A. & Perkovsky, Evgeny E., 2025, First record of the family Melyridae (Coleoptera: Cleroidea) in late Eocene European ambers with description of a new tribe, a new genus and seven new species, Zootaxa 5696 (4), pp. 542-566 : 553-555

Amelyris ( Asymelyris) paucidentatus Tshernyshev, Alekseev, Bukejs, Vasilenko, Legalov & Perkovsky , sp. nov.

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( Figs 14–16 )

Type material. Holotype No KAM 8636 [ KRAM], adult, male; Baltic amber . Complete beetle included in flat, irregular, transparent amber piece with approximate dimensions 43 × 26 × 7 mm, with the beetle situated in lateral part of the piece. Prosternum, mesosternum and head are not clearly visible due to milky-white coating and opacities in amber matrix. Syninclusions are represented by few stellate Fagaceae trichomes, many detrital particles and small plant fragments, numerous gas vesicles, one specimen of Collembola (Symphypleona), one specimen of Chalcidoidea ( Hymenoptera ), one insect larva (?Lepidoptera), and one imago of a beetle ( Coleoptera ), densely covered by milky coating. Locus typicus. Southeastern Baltic Sea coast, the Sambian peninsula, Kaliningrad Oblast. Stratum typicum. Baltic amber, late Eocene .

Description. Integument unicolorous black, without metallic lustre (as preserved), legs and antennae brown to light brown; dorsal setae brown. Body dilated, moderately elongate, depressed and moderately convex, evenly expanded just behind middle and narrowing at apex, with closed elytral apices. Measurements: body length (combined length of elytra, pronotum, and head along midline, measured dorsally) 3.25 mm; body maximum width across elytra 1.38 mm; pronotum length 0.7 mm; pronotum maximum width (at base) 0.95 mm; elytra width at base (combined) 1.0 mm; elytra length 2.25 mm.

Head prognathous, glabrous, convex, subrounded, not protruding distally and narrower than pronotum at eye level, transversely rugose in frons (forming shallow cell-like sculpture), finely punctate, covered with adpressed short hairs in vertex; compound eyes round-oval, vertical, bare, finely facetted; frons and interocular area evenly convex, lacking impressions. Antennae 11-segmented, attached to head near lower edge of eyes near clypeus, short, extending over middle but not reaching base of pronotum; ultimate antennomeres asymmetrically dilated, forming 5-segmented loose serrate antennal club). Antennomeres 1 and 2 swollen and enlarged, round-oval; antennomere 2 slightly shorter than antennomere 1; antennomeres 3–10 transversely triangular, with extremely extended outer edges; antennomere 3 small, narrowest; antennomeres 4–7 cylindrical, approximately equal in lengths, gradually widened, 1.5× as long as wide; antennomeres 8–10 triangular, dilated apically, about 1.5× as wide as antennomere 6; antennomere 11 flame-shaped, elongated, longitudinal, narrowed, truncate at apex. Terminal maxillary palpomere large, 3× as long as previous palpomere, narrowly triangular and narrowly rounded apically.

Pronotum convex, transverse, about 1.4× wider than long, trapezoidal in dorsal view, appears rectangular due to straight distal and basal margins and straight upper lateral carina, with rounded apical angles and acute basal angles, laterally with typical dicarinate margin: upper carina straight, lower carina rounded and distinctly prominent. Surface evenly densely punctured with strong punctures, distinct microsculpture, covered with fine, curved, slightly compressed hairs, giving the surface cellular appearance due to air retention by hairs in amber mass; margins of distal and basal sides and upper lateral carina smooth, lower lateral carina with denticles. Pronotal disc distinctly impressed: at anterior and posterior angles, along lateral upper carina.

Scutellar shield small, very short, transverse, about 0.5× as long as wide, rectangular, with acute angles and straight sides, surface sparsely punctured with small punctures and covered with fine adpressed pubescence; disc not marginate on sides, mat.

Elytra carinate, strongly dilated, suboval, slightly expanded just behind middle, about 1.6× as long as wide, evenly rounded and narrowed posteriorly with weakly stretched apex, completely cover abdomen; elytral apices separately rounded. Bases of elytra distinctly wider than pronotum. Humeri small, not prominent, with thin small rib located on each humerus and curving to third elytral carina. Elytral disc shiny. Each elytron with five thin and not strongly elevated carinae reaching from base to apical part; first carina located near suture, complete from base to apex, widened at elytral slope; carinae 2 and 3 reaching elytral slope, approximated but not merged; carina 4 shortened, begins at about humerus and ends at beginning of elytral slope; carina 5 strongly adjacent to epipleura and continues to elytral apex. Intervals between carinae wide; distance between rows of punctures equal to 0.5× diameter of one puncture; first interval 1.5× as wide as second one. Lateral sides of elytra flattened in apical half; lateral margin elevated and curved dorsally at elytral apex. Surface between punctures with distinct microsculpture; pubescence light, short and small, evenly distributed on carinae. Epipleura wide from base to middle of abdominal ventrite 1, then twice narrowed and distinct to apex; row of sparse punctures with microsculpture, distinct in middle of the widened part of epipleura; edges of epipleura smooth lacking denticles. Metathoracic wings well developed.

Legs short, simple, not flattened; impunctate, sparsely covered with fine, short pubescence. Femora thickened; tibiae evenly widened posteriorly, rounded. Tibial spurs spicular, short and sharp. Tarsomeres compressed; first tarsomere 1.5× as short as tarsomere 2 in anterior and intermediate legs and about 1.2× as short as tarsomere 2 in posterior legs; tarsomeres 2 and 3 equal in size; tarsomere 4 weakly shorter than tarsomere 3 in all legs; tarsomere 5 subcylindrical, as long as tarsomeres 2–4 combined. Tarsal claws broad, short; with not sharp, short and curved basal denticle.

Ventral side convex, shining, finely and sparsely punctate; pubescence fine, short and adpressed. Abdomen with five visible ventrites, finely and sparsely pubescent; intercoxal process narrowly triangular; ventrite 1 longest; ventrite 5 with wide and rounded emargination apically.

Etymology. The epithet of the new species paucidentatus is derived from the combined Latin adjective paucus (meaning ‘few, little’) and the Latin adjective dentatus (meaning ‘toothed’). The name refers to the comparatively few number of denticulate pronotal carinae.

Figures

FIGURES 14–16. Amelyris (Asymelyris) paucidentatus sp. nov., male, holotype, No. KAM 8636 [KRAM], microphotographs: 14—habitus in dorsal view; 15—habitus in ventral view; 16—details of pronotum and head, dorso-lateral view. Scale bars = 0.5 mm.