Rovnoscydmus microscopicus, Jałoszyński, Paweł & Perkovsky, Evgeny, 2016

Jałoszyński, Paweł & Perkovsky, Evgeny, 2016, Diversity of Scydmaeninae (Coleoptera: Staphylinidae) in Upper Eocene Rovno amber, Zootaxa 4157 (1), pp. 1-85 : 40-41

† Rovnoscydmus microscopicus sp. n.

( Figs 13 , 115–119 )

Type material. Holotype: Late Eocene of Europe , Rovno amber: sex unknown; inclusion in elongate, trapezoidal prism of amber 18 mm long ( Fig. 13 ), collection number K-347 ( SIZK).

Diagnosis. Rovnoscydmus with frons not demarcated from vertex; BL 0.64 mm; EI 1.47.

Description. Body ( Figs 115–119 ) elongate, slender and relatively strongly convex, brown; BL 0.64 mm.

Head ( Figs 115–119 ) broadest at eyes, HL 0.11 mm, HW 0.14 mm; vertex and frons confluent, together subtrapezoidal and moderately transverse; supraantennal tubercles weakly raised but distinct; compound eyes large, strongly convex, oval; tempora shorter than eyes. Punctures and setae on head poorly visible. Antennae ( Figs 115–119 ) slightly shorter than half BL, AnL 0.30 mm, antennal club indistinctly demarcated; antennomeres I–II elongate, III–VII each about as long as broad, VIII slightly transverse, IX and X slightly transverse, XI much shorter than IX–X combined, about 1.5 × as long as broad, with rounded apex.

Pronotum ( Figs 115, 117–118 ) elongate, broadest in front of middle; PL 0.18 mm, PW 0.15 mm; punctures on disc ( Fig. 118 ) small but distinct, separated by spaces 3–4 × as wide as diameters of punctures; setae poorly visible.

Elytra ( Figs 115 , 118 ) elongate oval, strongly convex, broadest in front of middle, EL 0.35 mm, EW 0.24 mm, EI 1.47; punctures similar to those on pronotum ( Fig. 118 ); setae poorly visible.

Legs ( Figs 115–119 ) moderately long, slender, unmodified.

Etymology. The name microscopicus refers to the extremely small body of this species.

Remarks. Rovnoscydmus microscopicus is much smaller than R. frontalis (BL 0.64 vs. 0.88 mm) and has stouter elytra (EI 1.47 vs. 1.64); it also has much larger eyes than R. frontalis . These characters are sufficient to treat these taxa as separate species.

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 115 – 117. Holotype of Rovnoscydmus microscopicus sp. n. (K- 347). Habitus in dorsolateral (115) and ventrolateral (116) views, head, pronotum and elytral bases in dorsal view (117).

FIGURES 118 – 119. Holotype of Rovnoscydmus microscopicus sp. n. (K- 347). Habitus in dorsolateral (118) and ventral (119) views. Abbreviations: abg, antebasal groove; bef, basal elytral fovea; bst, basisternal part of prosternum; bsti, basistipes; fr, frons; gp, gular plate; gs, gular suture; hw, hind wing; hy, hypomeron; mn, mentum; lbr, labrum; lp, labial palp; mcp, mesocoxal projection; md, mandible; mn, mentum; mtvp, metaventral intercoxal process; mxp 2 – 4, maxillary palpomere II – IV; nss, notosternal suture; pcr, procoxal rest; occ, occipital constriction; pg, pygidium; st 3 – 8, abdominal sternite III – VIII; tm, temple; v 2, mesoventrite; v 3, metaventrite; vt, vertex.