Clypastraea primainterpares, Alekseev, 2016

Alekseev, Vitalii I., 2016, New records and species of Crepidodera Chevrolat (Coleoptera: Chrysomelidae) in Eocene European amber, with a brief review of described fossil beetles from Bitterfeld amber, Baltic Journal of Coleopterology 16 (1), pp. 21-26 : 22-24

C. primainterpares sp. nov.

(Figs. 1 - 4)

Material examined. Holotype No. 1615-3 [ CCHH], adult, possibly female (evenly curved apical sternite). Inclusion in a small yellow amber piece, embedded in a block of GTSpolyester resin measuring 15 x 7 x 4 mm. Syninclusions are absent.

The amber piece was obtained from a commercial source and will be deposited at the Senckenber g Deutsch es Entomologisch es Institut (Müncheberg, Germany) as part of the institute amber collection.

Type strata. Baltic Amber, Eocene.

Type locality. Yantarny settlement, Sambian peninsula, Kaliningrad region, Russia .

Differential diagnosis.

The specimen under study corresponds to the diagnosis of the subfamily Corylophinae and the tribe Parmulini ( Ślipiński et al. 2009) . However, mandibles, labial palps, details of head, internal characters of abdomen and venation of hind wings are invisible in this specimen. The characters of the genus ( Bowestead 1999) are well discernible: anterior margin of prosternum sharply emarginated by antennal slots, leaving a truncate median plate; antennae 11-segmented, with well-formed club. These characters and the large body fit with the genus Clypastraea Haldeman, 1842 .

The narrow sutural interval indicates the probable placement of the newly described species into the orientalis group. C. primainterpares sp. nov. differs from C. maderae (Kraatz, 1869) in the smooth interspaces between punctures and from C. palmi Bowestead, 1999 in the fully developed hind wings and the comparatively long elytra. The Eocene beetle shows a distinctly larger body length than the recent south-European C. orientalis (Reitter, 1877) , which is only 1.1 - 1.46 mm long.

Description.

Habitus. Large (body length 1.67 mm, maximal body width 0.91 mm, maximal body height 0.57 mm), elongate, oval, moderately depressed, shortly pubescent. Color: entirely brown, slightly darker at center of the pronotal disc.

Head. Concealed, completely covered by the pronotum. Eyes large, oval. Mentum subquadrate. Submentum very short and broad. Antennae doubly geniculate in repose, 11- segmented, with a 3-segmented, weakly asymmetrical club. Pedicel and scape subequal in length. First and second segments of the club

Figures 1-3. Clypastraea primainterpares sp. nov. Holotype; No. 1615-3 [ CCHH]. Habitus: 1 - Dorsal view; 2 - Ventral view; 3 - Lateral view.

subtriangular; apical segment of the club oval, broad and rounded apically. Ratio of antennomere lengths: 5.0: 5.0: 2.0: 1.0: 1.0: 1.0: 2.0: 1.0: 4.0: 4.0: 5.0.

Thorax. Pronotum finely bordered; transverse (median length 0.48 mm; basal width 0.85 mm), with broadly arcuate anterior margin and slightly bisinuate posterior margin. Anterior angles absent, posterior angles straight. Pronotal punctuation dense, distinct (especially basally), round, separated by distance almost equal to that of a puncture diameter. Prosternal process flat, narrow between coxae, expanding posteriorly into a triangle meeting postcoxal projections. Anterior margin of the prosternum emarginated by antennal slots, leaving a truncate median plate. Mesepisternum and mesepimeron not separated by a suture. Sinuate line at base of the mesosternum not visible due to position of legs. Metepisternum narrowly triangular, slightly shorter than epipleuron, reaching the metacoxal cavities. Postcoxal lines absent. Scutellum triangular, rounded apically, transverse (1.4 times as wide as long).

Wings. Elytra broadest in anterior third; almost as wide as pronotal base anteriorly; elongate (sutural length 1.14 mm, maximal width 0.91 mm), separately rounded apically; irregularly punctured and recumbently pubescent. Puncture of elytra longitudinally oval, fine and

Alekseev V.I.

comparatively sparse, separated by distance 1.5- 2 times as diameter of punctures, with a long pubescence overlapping the next row of punctures, interspaces smooth and shining. Sutural stria long (two-thirds of the elytral length apically, not discernible in the basal third). Sutural interval narrow, with one row of punctures. Epipleura present, widest at humeral area; reaching the first ventrite. Metathoracical wings fully developed, partially exposed.

Legs. Pro- and mesocoxae rounded; procoxae narrowly separated by the prosternal process; distance between mesocoxae twice broader than mesocoxal diameter; metacoxae str on gly transverse, separated by distance 4 x that of the metacoxal diameter. Femora broad, flattened. Tibiae slender. Tarsi 4-segmented; last metatarsomere as long as tarsomeres 1 - 3 combined. Claws simple, long (three times sh or ter th an metatar somer e 4), cur ved, symmetrical.

Abdomen. With six visible ventrites. Ratio of ventrite lengths: 22.0-5.0-4.0-5.0-7.0-7.0. Basal ventrite without femoral lines. Last ventrite widely rounded apically.

Derivatio nominis. The specific epithet is derived from “primus inter pares” (feminine: prima inter pares), a Latin phrase meaning “first among equals”. The name is used as noun in apposition and refers to the habitual similarity to the recent congeners and Tertiary origin of the fossil specimen.