Rovnoscydmus

Jałoszyński, Paweł & Perkovsky, Evgeny, 2016, Diversity of Scydmaeninae (Coleoptera: Staphylinidae) in Upper Eocene Rovno amber, Zootaxa 4157 (1), pp. 1-85 : 48-51

† Rovnoscydmus sp. specimen 6

( Figs 19 , 145–150 )

Material studied. Late Eocene of Europe , Rovno amber: sex unknown; inclusion in elongate, triangular (with one corner rounded) prism of amber 17 mm long ( Fig. 19 ), collection number K-7350 ( SIZK).

Description. Body ( Figs 145–150 ) elongate, slender, nearly black; BL 1.10 mm.

Head ( Figs 145–150 ) broadest at eyes, HL about 0.25 mm, HW 0.28 mm; vertex and frons confluent, together subtrapezoidal and moderately transverse; supraantennal tubercles indistinct; compound eyes large, strongly convex, oval; tempora seem to be longer than eyes. Punctures on frons and vertex ( Fig. 148 ) fine and unremarkable, separated by spaces 3–4 × as wide as diameters of punctures; setae ( Fig. 148 ) sparse, short and suberect. Antennae ( Figs 145–150 ) much shorter than half BL, AnL about 0.40 mm, antennal club relatively well demarcated; antennomeres I–II strongly elongate, shapes of flagellomeres difficult to assess.

Pronotum ( Figs 145–150 ) nearly inversely trapezoidal, broadest near anterior fourth; PL 0.30 mm, PW 0.30 mm; punctures on disc ( Fig. 148 ) small but distinct, separated by spaces 2–4 × as wide as diameters of punctures; setae ( Fig. 148 ) short and sparse, suberect, on sides of pronotum replaced by distinct thick bristles ( Figs 145, 148 ).

Elytra ( Figs 145–150 ) elongate oval, broadest distinctly in front of middle, EL 0.55 mm, EW 0.45 mm, EI 1.22; punctures and setae similar to those on pronotum ( Fig. 148 ).

Legs ( Figs 145–146, 148–149 ) moderately long, slender, unmodified.

Remarks. Although this specimen is preserved in cloudy amber and only dorsal structures are partially exposed, the antennal structure, the shape of head, the elytra with one basal fovea each and measurements strongly suggest that this is also a Rovnoscydmus . The state of preservation does not allow for detailed comparisons, but this specimen is valuable because of the thick bristles visible on the right temple. Even in extant species of Glandulariini the bristles on the head and sides of prothorax may be difficult to observe under light microscopes, especially when they are short, mixed with 'regular' setae or sparse; sometimes they are partly broken off. The presence of bristles, within Scydmaeninae restricted to certain genera of Glandulariini , is treated as an important character state and whenever possible, it should be illustrated and described in fossils to facilitate further taxonomic or phylogenetic study.

Figures

FIGURES 1 – 20. Specimens of Rovno amber with inclusions of Scydmaeninae. K- 27418, Rovnoleptochromus ableptonoides sp. n. (1); K- 243, Vertheia quadrisetosa sp. n. (2); UA- 442, Vertheia sp. 1 (3); K- 800, Cephennodes sp. 1 (4); K- 6011, Cephennomicrus giganteus sp. n. (5); K- 8289, Cephennomicrus sp. 1 (6); K- 7010, Cephennomicrus sp. 2 (7); K- 27565, Cephennomicrus sp. 3 (8); K- 8912, Cephennomicrus sp. 4 (9); DU- 32, Cephennomicrus sp. 5 (10); K- 5770, Glaesoconnus unicus sp. n. (11); K- 9579, Rovnoscydmus frontalis sp. n. (12); K- 347, Rovnoscydmus microscopicus sp. n. (13); K- 25702, Rovnoscydmus sp. specimen 1 (14); K- 26348, Rovnoscydmus sp. specimen 2 (15); UA- 1556, Rovnoscydmus sp. specimen 3 (16); K- 8970, Rovnoscydmus sp. specimen 4 (17); K- 8968, Rovnoscydmus sp. specimen 5 (18); K- 7350, Rovnoscydmus sp. specimen 6 (19); K- 3037, Rovnoscydmus sp. specimen 7 (20).

FIGURES 145 – 150. Rovnoscydmus sp. specimen 6 (K- 7350). Dorsal (145, 148), dorsolateral (146, 149) and lateral (147, 150) views. Abbreviations: bef, basal elytral fovea; fr, frons; hw, hind wing; mcp, mesocoxal projection; nr, ' neck' region; tm, temple; vt, vertex.