Sucinorhagonycha samsockorum, Fanti & Pankowski, 2018

Fanti, Fabrizio & Pankowski, Mary K., 2018, Three new species of soldier beetles from Baltic amber (Coleoptera, Cantharidae), Zootaxa 4455 (3), pp. 513-524 : 516-519

Sucinorhagonycha samsockorum FANTI & M. K. PANKOWSKI sp. nov.

( Figs. 2–3 )

Description. Adult, winged, elongated, rather robust. Male, defined on the basis of the last sternite very small, narrow, rounded at apex, and separated and away from the last tergite. Body length: 4.5 mm; elytra: 3.3 mm; antennae: approximately 2.5 mm. Head black, elytra blackish to dark brown, pronotum with antennae and legs reddish to dark brown. Head very elongated and narrow, prognathous, completely exposed, wrinkled with shallow punctation and short setae. Eyes subelliptical, convex, inserted dorsally and near the sides of the head. Mandibles robust, elongated, slightly falciform, without teeth or denticles. Maxillary palps 4-segmented and unequal in length; first palpomere massive; second palpomere flat, robust, rounded and enlarged in the middle; third small, thin and short; last palpomere securiform, elongated, rounded externally, apically thin but with a bulbous tip. Labial palps 3-segmented, very elongated; first segment massive; second segment thin; last segment elongated, very slightly securiform with the apex robustly pointed. Antennae 12-segmented, inserted dorsally and between the eyes, very short, reaching and slightly surpassing the humeral zone, all segments pubescent along all margins; antennomere I (scape) filiform and robust, elongated, not club-shaped, slightly enlarged apically; antennomere II robust, short, 2.0 times shorter than scape, concave in the middle on the external side; antennomere III robust, slightly shorter than second article and not concave in the middle; antennomeres IV–V subequal, very slightly shorter than antennomere III, enlarged apically (dentate) on the external side; antennomere VI elongated, robust, approximately 1.5 times longer than antennomeres IV–V and not dentate on the external side; antennomere VII robust and the shortest, concave in the middle on the internal side; antennomere VIII filiform but slightly dentate at the external apex; antennomeres IX–XII filiform, unequal in length with the antennomere XII rounded at apex and the longest. Pronotum subquadrate, slightly longer than wide, very slightly wider than head, corners rounded, margins bordered, in the middle of the pronotum there is a large and very raised (evident) area slightly concave in the center, sides and margins flat after the raised area with shallow punctation and short pubescence. Scutellum not well visible. Elytra very elongated, slender, parallel-sided, completely covering the last abdominal segments, wider than pronotum, apex rounded, surface equipped with long and erected setae. Posterior wings completely covered by elytra. Metasternum blackish, punctate, elongated, posteriorly slightly rounded; sternites and tergites wide, punctate; last tergite short, wide and strongly bent at sides; last sternite small, narrow, rounded at apex. Anterior and median legs short, posterior legs longer; coxae massive, wide at base, elongated; trochanters elongated, posteriorly triangular; profemora strongly enlarged and slightly curved, meso- and metafemora thin; pro- and mesotibiae shorter than pro- and mesofemora, cylindrical, thin, with two spurs (one very short) and setae; metatibiae longer than metafemora, cylindrical, thin, with spurs and setae. Tarsi 5-segmented and with setae; pro– and mesotarsi with the first segment elongated, 1.5 times longer than second; metatarsi with the first tarsomere approximately 1.9 times longer than second; third tarsomere shorter than second and slightly enlarged apically; fourth tarsomere bilobed at sides with the lobes very long, curved and rounded at apex; fifth tarsomere elongated, thin; claws simple, long and without lobes or denticles.

Etymology. Species named after Frank and Joanne Samsock, maternal grandparents of the second author, who worked hard, dedicated their lives to their family and were excellent role models for their children and grandchildren.

Holotype. Male, adult specimen included in Baltic amber, accession No. USNM PAL 712533 in the USNM.

Type locality. Yantarny settlement (formerly Palmnicken ), Sambian (Samland) Peninsula, Kaliningrad Region, Russia.

Type strata. Baltic amber, Upper Eocene , Prussian Formation (Priabonian). Estimated age: 37.8–33.9 Mya.

Syninclusions. Many wood remains and masses of plant fragments (detritus).

Differential diagnosis. Antennae with 12 antennomeres and the claws without lobes of the new species suggest that it belongs to the genus Sucinorhagonycha . (For more details, see the key below.) The genus is easily distinguishable from the fossils of the family Cantharidae Imhoff, 1856 with its 12-segmented antennae present only in Cacomorphocerus Schaufuss, 1892 (for the differences, see Discussion section below) and the extant Australian genus Heteromastix Boheman, 1858 (Subfamily Dysmorphocerinae Brancucci, 1980 ), which also sometimes has 12 antennal articles ( Brancucci 1980; Fanti 2017c), with the antennomeres X–XI strongly modified ( Brancucci 1980; Kuśka 1996). Only one other species of Sucinorhagonycha has been described, S. kulickae Kuśka, 1996 , which is known on the basis of a male and a female found in different Baltic amber pieces ( Kuśka 1996; Kubisz 2000; Fanti 2017a). Sucinorhagonycha samsockorum sp. nov. differs from both sexes of S. kulickae because its antennal articles IV–V are slightly dentate (compared to filiform in S. kulickae ), and because its pronotum is not transverse and has two evident central thickenings (while in S. kulickae the pronotum has a longitudinal central linear depression and protuberances on the sides). In addition, the male of S. kulickae has shorter antennomeres than S. samsockorum sp. nov.

Remarks. The yellow amber piece has a spherical shape measuring 15x14 x 11 mm and weighs 1.3 grams. The inclusion is complete and well visible.

Figures

FIGURE 2. Sucinorhagonycha samsockorum sp. nov. in Baltic amber. A–B: Holotype, lateral views, scale bar = 1.0 mm. C: Holotype, detail of palps, scale bar = 0.4 mm. D: Holotype, detail of antenna, scale bar = 0.5 mm.

FIGURE 3. Sucinorhagonycha samsockorum sp. nov. in Baltic amber. A: Holotype, detail of legs, scale bar = 0.5 mm. B: Holotype, detail of last sternites, scale bar = 0.5 mm.