Cephennodes

Jałoszyński, Paweł & Perkovsky, Evgeny, 2016, Diversity of Scydmaeninae (Coleoptera: Staphylinidae) in Upper Eocene Rovno amber, Zootaxa 4157 (1), pp. 1-85 : 21-22

Cephennodes (incertae sedis) sp.

( Figs 4 , 65–70 )

Material studied. Late Eocene of Europe , Rovno amber: sex unknown; inclusion in an elongate prism of amber 16 mm long ( Fig. 4 ), collection number K-800 ( SIZK).

Description. BL 1.35 mm. Body ( Figs 8–15 ) elongate but stout, relatively strongly convex, constriction between pronotum and elytra shallow, pigmentation dark reddish-brown.

Head short, HL 0.18 mm, HW 0.25 mm; compound eyes oval, large; vertex and frons weakly convex, confluent and unmodified; supraantennal tubercles indistinct. Antennae moderately long and relatively slender, with three terminal antennomeres forming indistinctly demarcated club; AnL 0.60 mm; all antennomeres elongate, XI slightly shorter than IX and X combined, slightly broader than X, about twice as long as broad, with blunt apex.

Pronotum in dorsal view ( Figs 65, 68 ) semioval with rounded anterior margin, strongly transverse, PL 0.43 mm, PW 0.53; lateral pronotal carinae ( Fig. 68 ; lpc) narrowly demarcated from disc; sides rounded; posterior pronotal corners acute; posterior margin shallowly bisinuate; lateral antebasal pits ( Fig. 68 ; abp) distinct, large but shallow, each located slightly closer to posterior than to lateral pronotal margin. Pronotal disc covered with fine but sharply marked punctures separated by spaces about 2–3 times as wide as diameters of punctures; setae sparse, short and suberect ( Fig. 68 ).

Elytra ( Figs 65–66, 68–69 ) elongate, oval, more convex than pronotum; EL 0.75 mm, EW 0.63 mm, EI 1.20; each elytron with small humeral denticle, subhumeral line indiscernible; basal elytral fovea ( Fig. 68 ; bef) located slightly closer to lateral margin of large, subtriangular mesoscutellum than to humeral denticle. Punctures on elytra slightly larger but shallower than those on pronotum, with diffused margins, separated by spaces about 1–2 times as wide as diameters of punctures; setae similar to those on pronotum ( Fig. 68 ).

Legs ( Figs 66–67, 69–70 ) moderately long and slender, unmodified; all tibiae straight or nearly straight.

Remarks. This specimen can be identified as Cephennodes Reitter, 1884 on the basis of the following characters, well observable in the inclusion: the suboval body form ( Figs 65–70 ); the subconical and truncated maxillary palpomere IV ( Fig. 70 ; mxp4); the head lacking occipital constriction and strongly declined; the prothorax with lateral pronotal carinae ( Fig. 68 ; lpc) and a pair of lateral antebasal pits ( Fig. 68 ; abp); each elytron with one distinct and setose basal fovea ( Fig. 68 ; bef); the mesoventral intercoxal process broad ( Fig. 70 ; msvp) and anteriorly flanked by distinctly demarcated subtriangular impressed areas functioning as procoxal rests; and the metaventral intercoxal process ( Fig. 70 ; mtvp) broad, short and emarginated.

As discussed previously ( Jałoszyński & Kubisz 2016), extant species of Cephennodes are externally very uniform, and the primary diagnostic characters to define species are associated with male secondary sexual modifications of various body parts and the aedeagus. The subgenera of Cephennodes are also defined on the basis of genital characters, and therefore a species that lacks any conspicuous modifications can be assigned to a subgenus only if males are available. The sex of the Eocene species is unknown and all visible body parts of this specimen are unmodified. The habitus of this specimen can be regarded as 'generalized' and typical of many unremarkable extant species. Consequently, the Eocene specimen cannot be reliably distinguished from many similar extant species or unambiguously diagnosed as new, and it is here treated as Cephennodes (incertae sedis) sp.

The specimen from Rovno amber is distinctly smaller than Cephennodes sp. recorded recently from Baltic amber ( Jałoszyński & Kubisz 2016), it is 1.35 mm long, whereas the Baltic beetle is 1.73 mm long; they also clearly differ in proportions of body parts (EI 1.20 vs. 1.09 respectively in Rovno vs. Baltic amber taxa) and the development of subhumeral lines (long and distinct in the Baltic amber specimen vs. indiscernible in the Rovno inclusion). Therefore, these are almost certainly different 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 65 – 70. Cephennodes sp. 1 (K- 800). Dorsal and slightly lateral (65, 68), lateral (66, 69) and ventral and slightly lateral (67, 70) view. Abbreviations: abp, antebasal pits; bef, basal elytral fovea; bst, basisternal part of prosternum; hy, hypomeron; hyr, hypomeral ridge; lpc, lateral pronotal carina; mcp, mesocoxal projection; mscc, mesocoxal cavity; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; mxp 2 – 4, maxillary palpomere II – IV; st 3 – 8, abdominal sternite III – VIII; v 3, metaventrite.