Cephennodes

Jałoszyński, Paweł & Kubisz, Daniel, 2016, First records of Chevrolatiini and Cephenniini in Eocene Baltic amber (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4114 (5), pp. 572-580 : 576

Cephennodes (incertae sedis) sp.

( Figs 2 , 8–15 )

Material studied. Inclusion in subtriangular amber piece ( Fig. 2 ), length 23 mm, beetle nearly entirely exposed, but some structures obscured by a milky 'cloud' surrounding abdomen and mouthparts, sex unknown; Eocene Baltic amber, collecting details unknown ( ISEA, catalog No. MP/514; donation of Jacek Serafin, Poland).

Description. BL 1.73 mm. Body ( Figs 8–15 ) elongate but stout, relatively strongly convex, constriction between pronotum and elytra shallow, pigmentation dark reddish-brown.

Head elongate, HL 0.38 mm, HW 0.30 mm; compound eyes oval, large and adjacent to antennal cavities; vertex convex; frons flattened, unmodified; supraantennal tubercles weakly raised. Punctures of head fine, inconspicuous; setae on frons and vertex short, sparse, suberect. Labrum large, nearly semicircular; mandibles long and slender, strongly curved ventromesally; maxillary palp with palpomere III broadest near distal third, palpomere IV about as long as broad, subconical with truncate apex. Antennae moderately long and slender, with three terminal antennomeres forming indistinctly demarcated club; AnL 0.65 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. Antennae covered with sparse, short and recumbent to suberect setae.

Pronotum in dorsal view ( Fig. 12 ) subrectangular with rounded anterior margin, strongly transverse, PL 0.48 mm, PW 0.68; lateral marginal carinae barely noticeably microserrate and narrowly demarcated from disc; sides weakly rounded; posterior pronotal corners nearly right-angled; posterior margin shallowly bisinuate; lateral antebasal pits distinct, large but shallow, each located slightly closer to lateral than to posterior pronotal margin. Pronotal disc covered with fine but sharply marked punctures, those in median area separated by spaces about twice as wide as diameters of punctures; setae sparse, short and suberect.

Elytra ( Figs 8 , 12 ) elongate, oval, more convex than pronotum; EL 0.88 mm, EW 0.80 mm, EI 1.09; each elytron with small humeral denticle, subhumeral line as long as about 0.25 EL and distinct basal elytral fovea located at middle between lateral margin of large, subtriangular mesoscutellum and subhumeral line. Punctures on elytra distinctly larger but shallower than those on pronotum, with diffused margins and those in anterior half of each elytron separated by spaces about 1.5 times as wide as diameters of punctures; setae longer than those on pronotum, moderately sparse, suberect.

Legs ( Figs 8–15 ) moderately long and slender, unmodified; all tibiae straight or nearly straight.

Remarks. This specimen can be unambiguously determined as Cephennodes Reitter, 1884 , the type genus of Cephenniini Reitter, 1882 , on the basis of the suboval body form; the subconical and truncated maxillary palpomere IV; the long and nearly semicircular labrum; the long mandibles strongly curved ventromesally; the head lacking occipital constriction and strongly declined; the pronotum with lateral marginal carinae and a pair of lateral antebasal pits; the prosternal process subtriangular and elongate in ventral view; each elytron with one distinct basal fovea and subhumeral line; the mesoventral intercoxal process broad and anteriorly flanked by distinctly demarcated subtriangular impressed areas functioning as procoxal rests; and the metaventral intercoxal process broad, approximately trapezoidal and emarginated.

Extant species of Cephennodes are externally uniform, so that primary diagnostic characters of species are associated with male secondary sexual modifications of various body parts (useful to subdivide Cephennodes into informal species groups) and the aedeagus. Even subgenera of Cephennodes are defined on the basis of genital characters, and therefore a species that shows no particular modifications can be assigned to a subgenus only if males are available. The sex of the Eocene species is unknown, all visible body parts of this specimen are unmodified, and it represents a 'generalized' habitus, typical of many unremarkable extant species that can be identified only on the basis of the aedeagus. Consequently, the Eocene specimen cannot be unambiguously distinguished from many very similar extant species and it is here treated as Cephennodes (incertae sedis) sp.

Figures

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

FIGURES 8 – 11. Eocene Cephennodes sp. in dorsal (8), right lateral (9), right lateroventral (10) and left lateral (11) views.

FIGURES 12 – 15. Eocene Cephennodes sp. in dorsal (12), ventral (13), left lateral (14) and right lateral (15) views.