Trochoideus resinatissimus, Alekseev & Tomaszewska, 2018

Alekseev, Vitalii I. & Tomaszewska, Wioletta, 2018, New handsome fungus beetles (Coleoptera: Coccinelloidea: Anamorphidae, Endomychidae) from European amber of the Upper Eocene, Palaeontologia Electronica (6 A) 21 (1), pp. 1-23 : 15-17

Trochoideus resinatissimus sp. nov.

Figures 5.6 -7, 6.1-2

zoobank.org/ 2456F93D-89AA-4850-8452-99A33CF5E6B4

Type material. Holotype No. 53-2 [ CCHH], sex unknown. The beetle is included in a polished piece of transparent amber with an orange shade. The amber was not subjected to any additional fixation. Measurements of the amber piece are 20 mm x 17 mm x 5 mm. The amber piece was possibly subjected to thermal and high-pressure processing in an autoclave.

Type strata. Bitterfeld amber. Eocene.

Type locality. Germany, Sachsen-Anhalt, Goitzsche (Bitterfeld-Wolfen) .

Etymology. The epithet of the new species is Latin adjective “resinatus” (resinous) in the superlative.

Diagnosis. Trochoideus resinatissimus differs from congeneric and probably coeval species described above from Baltic amber, based on antennal structure (strongly transverse antennomere 4 and egg-shaped antennomere 5) and larger body.

Description. Body elongate, convex, uniformly dark. Total body length 4.1 mm, elytral length 2.7 mm, width (at widest point in middle of elytra) 2.0 mm.

Compound eyes prominent and coarsely facetted. Antennae short, extending to middle of pronotum; composed of five antennomeres, claviform. Antennomere length proportions follow formula: 3.2: 1.2: 1.4: 1.0: 8.0. Penultimate antennomere strongly transverse (three times as wide as long). Terminal antennomere egg-shaped, rounded apically, 2.0 times as long as wide. Terminal labial palpomere almost spherical. Maxillary palp with terminal palpomere as long as penultimate one, oblong and acuminate. Anterior angles of pronotum widely-rounded. Metathorax coarsely and densely punctate. Distance between metacoxae wider than distance between mesocoxae. Elytra laterally with fine, irregular, slightly longitudinally oval punctures. Apex of elytra with distinct and fine parasutural stria. Legs with tarsal formula 4-4-4. Abdomen with six ventrites, and ventrite 1 longest.

Remarks. The specimen is dorsally covered with dense milky cover, so the characters of upper surface are not visible (except lateral and apical parts of the elytra).

Note. According to the note given under the description of Trochoideus koenigsbergicus (above) from Baltic amber, the new species from Bitterfeld amber could theoretically be the male of the same, widely distributed Eocene species. The thickened antennomere 4 of T. resinatissimus and different form of other antennomeres could be interpreted as sexual characters only. However, the question about reliable specific differences between specimens from Baltic and Bitterfeld amber would require further study of additional fossil material from both deposits.

Figures

FIGURE 5. Endomychids from Baltic and Bitterfeld ambers. 1-3, Laima andreei gen. et sp. nov. (No. 1222-5 [CCHH], holotype), habitus in lateral (1), dorsal (2), and ventral (3) views. 4-5, Trochoideus koenigsbergicus sp. nov. (No. 1506-1 [CCHH], holotype), habitus in dorsal view (4), and antenna in lateral view (5). 6-7, Trochoideus resinatissimus sp. nov., antenna (6) and maxillary palp (7) in lateral views.