Amelyris ( Asymelyris ) groehni Tshernyshev, Alekseev, Bukejs, Vasilenko, Legalov

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 : 558-560

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

urn:lsid:zoobank.org:act:

( Figs 20–25 )

Type material. Holotype No. GPIH 5223, CCGG 8709 (ex coll. Jonas Damzen JDC-6437), male; Baltic amber . A flat piece of transparent amber 30×18× 8 mm in size and preserved without supplementary fixation. Ventral side of the specimen partially covered by milky-white coating. Syninclusions consist of few stellate Fagaceae trichomes.

Paratype No. ABAC 066 [ABAC] (ex coll. Jonas Damzen JDC-8916), female; Baltic amber . A flat piece of transparent amber 48×30× 8 mm in size and preserved without supplementary fixation, with the beetle situated in lateral part of the piece. Syninclusions consist of one small spider specimen ( Araneae ), few stellate Fagaceae trichomes and detrital particles .

Paratype No. GPIH 5225 , CCGG C-4746 , male; Baltic amber. A flat piece of transparent amber 25×17× 6 mm in size and preserved without supplementary fixation, with the beetle situated in lateral part of the piece. Ventral side of the specimen covered by milky-white coating and opacities of amber matrix. Syninclusions consist of one Brachycera (Diptera) specimen and few stellate Fagaceae trichomes .

Paratype No. GPIH 5224, CCGG 8710 (ex coll. Jonas Damzen JDC-12535), sex unknown; Baltic amber . A flat piece of transparent amber 25×11× 4 mm in size and preserved without supplementary fixation. Syninclusions consist of few stellate Fagaceae trichomes .

Locus typicus. Southeastern Baltic Sea coast , the Sambian peninsula , Kaliningrad Oblast.

Stratum typicum. Baltic amber, late Eocene.

Description of holotype. Body elongate, suboval, weakly depressed and moderately convex, evenly dilated and rounded posteriorly with straightly cut apex); unicolorous dark brown, without metallic luster; pubescence: head, pronotum and elytra with short, fine, recumbent to semi-erect setae, ventral side of specimen with inconspicuous, recumbent setation. Measurements: body length (pronotum + elytra) 2.54 mm, maximum body width 1.15 mm; pronotal length 0.54 mm, pronotal maximum width 0.84 mm; elytral length 2.0 mm, elytra width at base 0.92, elytral maximum width (in posterior one-third) 1.15 mm.

Head prognathous, slightly convex, round, not stretched distally and not wider than pronotum at level of eyes; evenly and finely punctate. Compound eyes oval, rather small, slightly prominent, bare. Frons and interocular area flat. Antennae 11-segmented, with lose 5-segmented club, inserted near lower inner edge of eye near clypeus, narrow, slightly elongate, reaching base of elytra, sparsely covered with fine, erect setae; antennomeres 5–10 evenly widened towards apex, subtriangular to triangular, asymmetric, with stretched outer edges; antennomeres 1 and 2 subcylindrical, swollen and slightly enlarged, elongate, 1.7× as long as wide, subeqal in size; antennomere 3 conical, slightly dilated apically, 1.7× shorter and narrower than antennomere 2; antennomere 4 subconical, about as long as antennomere 3; antennomeres 5 and 6 subtriangular, elongate, slightly longer and wider than antennomere 4; antennomeres 7–8 triangular, about as long as wide; antennomeres 9–10 widely triangular, transverse, 1.3× as wide as long; antennomere 11 elongate, 1.5× as long as wide, subconical, wide basally and narrowed apically. Clypeus slightly narrowed anteriad, slightly convex medially. Labrum distinct, slightly transverse, distinctly narrowed anteriad, subtrapezoidal with rounded, not emarginate distal margin, not covers mandibles. Mandibles short, apparently bidentate. Maxillary palpi narrow; ultimate palpomere elongate, 2.3× as long as wide, conical, evenly narrowed to apex, about 2.5× as long as penultimate antennomere.

Pronotum convex, transverse, 1.6× as wide as long, evenly rounded and narrowed anteriorly, with acute and slightly protruding posterior angles; laterally with double carinate side: upper carina widely rounded, not protruding, distinctly serrate, lower carina almost straight, curved inward medially along disc, apparently smooth, lacking small protuberances or denticles. Surface with large, irregular cells and dense micropunctation. Pronotal disc with weak, narrow, longitudinal impression medially; distinctly impressed posterorolaterally and along lateral sides, weakly impressed along anterior side.

Scutellar shield rather large, subtrapezoidal, weakly transverse, 1.3× as wide as long, densely covered with fine punctation.

Elytra carinate, subparallel-sided, elongate and suboval, 1.7× as long as wide, slightly widened at apical one-third, evenly rounded posteriorly with apices closed and straightly cut. Lateral sides strongly flattened from base to apices. Base of elytra slightly wider than pronotum; elytra cover abdomen completely. Humeri small, slightly protruding, not impressed, narrow carina short and distinct at base of humerus only. Each elytron with five narrow, distinctly convex carinae; carina 1 located near elytral suture and almost completely coincides with margin of suture, but distinctly separated at elytral slope forming ‘widened’ appearance to suture; carinae 2 and 3 entire from base to slope of elytra and not merged on slope; carina 4 started under humerus and continued to elytral slope; carina 5 distinct from base to elytral apices. Interspaces between carinae with three rows of rather large punctures and dense micropunctation. Epipleura not vertical, wide, evenly narrowing posteriad, reaching elytral apices, with row of sparse, small punctures and microsculture, lateral margins of epipleura with small inconspicuous denticles. Metaventrite with disc convex, densely covered with fine punctation. Metanepisternum wide, about 4.4× as long as wide; with dense micropunctation. Metathoracic wings well developed and partially exposed from under right elytral apex.

Legs short, simple, covered with fine recumbent setae. Femora evenly narrowly suboval, flattened, with dense and fine punctation. Tibiae evenly slightly dilated to apex; with fringe of stout, dark setae apically and apparently with two fine apical spurs. Tarsi compact, all tarsi 5-segmented, with setation ventrally, tarsomeres 1–4 subconical, slightly dilated apically, tarsomere 5 subcylindrical, slightly curved, elongate; tarsomere 1 shortest, about 0.8× as long as tarsomere 2; tarsomeres 2–4 nearly equal size; tarsomere 5 longest in all legs, as about as long as tarsomeres 2–4 combined. Claws small, sharp, symmetrical, with elongated basal tooth.

Abdomen with six visible ventrites, densely covered with fine punctation, ventrites 1 and 2 apparently connate. Pygidium and last ventrite simple, not emarginate or depressed, and lacking tufts of hairs; pygidium slightly elongate and domelike; last ventrite with apical margin widely rounded and covered with fine, erect setae.

Paratype GPIH 5225 , CCGG C-4746 , male. Measurements: total body length (pronotum + elytra) 2.92 mm (3.0 mm including visible part of head), body maximum width 1.15 mm. Pronotal length 0.69 mm, pronotal maximum width 0.92 mm. Elytral length 2.23 mm, elytral width at base 1.0 mm, elytral maximum width (in posterior one-third) 1.15 mm. Otherwise, this specimen is similar in all visible morphological characters to holotype No. 5223 [ GPIH].

Paratype No. ABAC 066 , female. Measurements: total body length (pronotum + elytra) 2.46 mm ( 2.61 mm including visible part of head), maximum body width 1.15 mm; pronotal length 0.54 mm, pronotal maximum width 0.84 mm; elytral length 1.92 mm, elytral width at base 0.92 mm; elytral maximum width (in posterior one-third) 1.15 mm.

It differs from male by more slender antennae with elongate and more narrower antennomeres forming indistinct club; inner margin of epipleurae with distinct small denticles more distinctly prominent posteriorly (probably due to clear visibility of beetle in amber piece, while epipleura poorly visible in holotype); legs more narrower, especially tibiae, tarsi thinner and shorter, but claws longer. Otherwise, this specimen is similar in all visible morphological characters to holotype No. 5223 [ GPIH].

Paratype GPIH 5224 , CCGG 8710 , sex unknown. Measurements: total body length (pronotum + elytra) 3.0 mm ( 3.1 mm including visible part of head), body maximum width 1.2 mm; pronotal length 0.7 mm, pronotal maximum width 0.8 mm; elytral length 2.3 mm, elytral width at base 0.9 mm, elytral maximum width (in posterior one-third) 1.2 mm. Otherwise, this specimen is similar in all visible morphological characters to holotype No. 5223 [ GPIH].

Etymology. The specific epithet is a patronym; the new species is named in honor of Mr. Carsten Gröhn (Glinde, Germany), an enthusiast and specialist in Baltic amber.

Figures

FIGURES 20–25. Amelyris (Asymelyris) groehni sp. nov., microphotographs, habitus: 20—holotype, No. GPIH 5223, dorsal view; 21—holotype, ventral view; 22—paratype, No. ABAC 066, dorsal view, 23—paratype, No. ABAC 066, ventral view; 24— paratype, No. GPIH 5224, dorso-lateral view; 25—paratype, No. GPIH 5225, dorso-lateral view. Scale bars = 0.5 mm.