Chevrolatia sp.

Jałoszyński, Paweł & Kubisz, Daniel, 2016, First records of Chevrolatiini and Cephenniini in Eocene Baltic amber (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4114 (5), pp. 572-580 : 574-575

Chevrolatia sp.

( Figs 1 , 3–5 )

Material studied. Inclusion in flat, oval amber piece ( Fig. 1 ), longer diameter 8 mm, beetle exposed in lateral view, details of dorsal and ventral sides not visible, sex unknown; Eocene Baltic amber, Lithuania; collecting details unknown ( MNHW; donation of Albert Allen, USA).

Description. BL 1.73 mm (exposed abdominal apex excluded). Body ( Figs 3, 5 ) elongate and relatively strongly convex, dark brown.

Head ( Figs 3–5 ) strongly elongate, HL 0.30 mm; compound eyes nearly round and adjacent to antennal cavities, tempora nearly twice as long as eyes; posterior portion of head strongly depressed up to occipital constriction, 'neck' region partly exposed, elongate; maxillary palps with minute proximal palpomeres, palpomere III large, strongly broadening from base to apex, palpomere IV broad and short, obliquely truncate. Head with moderately long and sparse suberect setae, vertex with setae directed dorsoposteriorly, 'neck' region with setae directed dorsoanteriorly ( Fig. 4 ). Antennae ( Figs 3, 5 ) long and slender, gradually but weakly broadening distally; AnL 0.93 mm; scape nearly three times as long as broad, broadened distally; pedicel elongate but much shorter than scape, subcylindrical; antennomeres III–IV each slightly elongate, V–VI distinctly elongate, VII–VIII about as long as broad, IX–X slightly longer than broad, XI shorter than IX and X combined, slightly broader than X, about twice as long as broad, with rounded apex. Antennae covered with sparse and moderately long suberect to erect setae.

Shape of pronotum not possible to assess, probably elongate bell-shaped or subtrapezoidal, PL 0.40 mm; entire lateral margin carinate; traces of lateral antebasal impressions visible near posterior pronotal corners, possibly also transverse impression is present. Pronotal disc covered with sparse, moderately long erect setae.

Elytra ( Figs 3, 5 ) elongate, more convex than pronotum; EL 1.03 mm; dorsal surface only partly visible, covered with moderately long and sparse erect setae.

Legs ( Figs 3, 5 ) long and slender, unmodified; all tibiae appear straight or nearly straight.

Pygidium ( Fig. 5 ) exposed, subtriangular.

Remarks. The Eocene specimen can be unambiguously placed in the extant tribe Chevolatiini on the basis of its remarkable body shape, especially the head, which is posteriorly depressed and has dorsal and ventral setae in front of and behind the occipital constriction directed towards the constriction ( Fig. 4 ); the structure of maxillary palpomeres III and IV; the gradually thickened antennae that can bend between the scape and pedicel and with distinctly enlarged scape; and the exposed pygidium. All these characters are similar to those diagnostic of the extant species of Chevrolatia Jacquelin du Val, 1850 ( Figs 6–7 ), the only genus of Chevrolatiini. Except for unusually convex elytra and the pronotal lateral carinae extending from anterior to posterior pronotal margins (more flattened elytra and usually incomplete lateral pronotal carinae in extant species), the Eocene specimen does not differ from known species of Chevrolatia . The differences are minor and do not justify establishing a separate genus. This interesting species is very similar to extant members of Chevrolatia and formal description as a new and named species is not possible because of lack of reliable diagnostic characters.

Figures

FIGURES 1 – 2. Eocene Baltic amber with inclusions: Chevrolatia sp. (1) and Cephennodes sp. (2).

FIGURES 3 – 7. Eocene Chevrolatia sp. (3 – 5) and extant Ch. egregia Reitter (Bulgaria) (6 – 7). Habitus in lateral view (3, 5 – 6), and head in right lateral view (4, 7).