Lilioceris groehni, Bukejs, Andris & Schmitt, Michael, 2016

Bukejs, Andris & Schmitt, Michael, 2016, Liliocerisgroehni sp. n.: the first authentic species of Criocerinae (Coleoptera, Chrysomelidae) from Baltic amber, ZooKeys 618, pp. 67-77 : 69-71

Taxon classification Animalia Coleoptera Chrysomelidae

Lilioceris groehni sp. n. Figs 1-2, 3-5

Type material.

Holotype: Nr. "C 8130" [GPIH]; female. A rather complete beetle (missing apical antennomere of left antenna, and tarsomeres 4 and 5 of left meso- and metatarsi) is included in a small, transparent yellow amber piece (length about 20 mm, width 12 mm, and maximum thickness 5 mm). Syninclusions: one specimen of Nematocera ( Diptera ), and few stellate Fagaceae trichomes (Figs 1 and 2).

Type strata.

Baltic amber, mid-Eocene to Upper Eocene.

Type locality.

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

Differential diagnosis.

Head, body, and elytra of Lilioceris groehni sp. n. appear unicolorous black and thus similar to the extant species Lilioceris hitam Mohamedsaid, 1990 from Borneo, which differs from the new species in (1) the shape of the pronotum (distinctly longer than wide with its constriction at the middle), (2) metaventrite glabrous in the middle, (3) pubescent scutellum, (4) impunctate elytra (with few moderately large punctures at base only), (5) vertex with sparse pubescence, (6) a distinct conical neck between head and pronotum, and (7) a larger body (10 mm).

Additionally, the extant species Lilioceris lilii Scopoli, 1763 and Lilioceris merdigera Linnaeus, 1758 from Baltic region differ from Lilioceris groehni sp. n. in having (1) a pronotum with a longitudinal row of punctures medially, (2) metaventrite, metepisternum and ventrites of abdomen almost glabrous or with very sparce pubescence, and (3) pronotum and elytra rufous to red.

Description.

Holotype. Body length 7.1 mm, maximum width 4.1 mm; elongate, subparallel, moderately convex dorsally and ventrally, unicolorous black, glabrous dorsally.

Head hypognathous, transverse, widest across eyes, together with eyes nearly as wide as pronotum, strongly constricted behind the eyes forming a neck (Fig. 3); shiny, hairless and without distinct punctures dorsally. Compound eyes large, strongly convex, deeply and acutely notched at antennal insertions; distance between eyes nearly as wide as transverse diameter of one eye. Frontal grooves deep, crossed forming X. Vertex convex, hairless, with median longitudinal groove. Genae large, with sparse pubescence. Antennae poorly visible because of a beetle location in amber piece. Antennae robust, covered with fine pubescence, moderately long, extending nearly to basal one-fourth of elytra, slightly widened apically; antennomere 2 shortest, about 0.4 times as long as antennomere 3, antennomere 4 sligthly longer than antennomere 3, antennomeres 5-7 subeqal in length, antennomere 5 about 1.2 times as long as antennomere 4.

Pronotum nearly as long as wide, deeply constricted medially, distinctly narrower than elytra, widest in anterior one-third; impunctate, shiny; disc flattened, with an arcuate transverse depression subbasally (Figs 3 and 4). Anterior margin straight me dially; posterior margin convex; lateral margins rounded anteriorly and strongly constricted just behind middle; all margins not bordered. Anterior and posterior angles obtusely rounded.

Scutellum large, triangular; apparently hairless and impunctate. Elytra subparallel, widest in the middle, about 1.5 times as long as wide; humeri prominent. Elytral punctures small and dense (in basal one-third deeper), arraged in rows; scutellar row present, short; intervals flat, only at apices weakly convex.

Metaventrite with sparse, fine pubescence; metepisternum and metepimeron densely covered with fine, short, semierect pubescence. Abdomen with sparse, fine pubescence.

Legs moderately long, covered with fine pubescence. Femora spindle-shaped; tibiae slightly curved, dilated apically. Tarsi long, about 0.7 times as long as tibia; metatarsomeres 1-2 subequal in length, distinctly dilated apically, metatarsomere 3 deeply bilobed, metatarsomere 4 subcilyndrical, narrow. Tarsal claws free, not fused at base.

The interior of the abdomen does not contain any identifiable structure, as revealed by the microCT-analysis. No traces of an aedeagus could be found, and none of the smaller particles - all covered with homogeneous material - could be addressed as the spermatheca.

Derivatio nominis.

This new species is named after Carsten Gröhn (Glinde, Germany) - he enabled us to study this specimen.