Cacomorphocerus thomasiwentzeli, Wentzel & Bonino & Fanti, 2022

Wentzel, Danuta, Bonino, Enrico & Fanti, Fabrizio, 2022, A new Cacomorphocerus Schaufuss, 1892 (Cantharidae) from Baltic amber, Baltic Journal of Coleopterology 22 (2), pp. 313-318 : 314-316

Cacomorphocerus thomasiwentzeli sp. nov.

( Figs. 1–2 )

Holotype. Male , adult specimen in Baltic amber piece, with the Catalog number 452 in the Danuta Wentzel collection (Ennepetal, Germany).

Type locality. Kaliningrad region, Russia.

Type horizon. Middle Eocene: Lutetian (47.8– 41.2 Mya) to late Eocene: Priabonian (37.8– 33.9 Mya).

Differential diagnosis. The most similar Cacomorphocerus Schaufuss, 1892 with 12 antennomeres is Cacomorphocerus wiszniewskii

Fanti & Kupryjanowicz, 2018 from which the new species differs for the antennomere VIII longer and more curved and antennomere IX more transverse and thinner.

Description. Adult, alate. Male, based on last sternite extremely small and transverse, and based on the presence of long appendage which is probably part of the aedeagus. Body length: 6.2 mm (the body is curled up and in life probably reached about 7 mm). Entirely dark brown.

Head rounded at sides, short and slightly transverse, as large as pronotum, equipped with long setae and shallow punctuation. Eyes rounded, convex and very prominent, inserted laterally to the head in the upper part. Mandibles elongated, falciform, apparently without tooth. Maxillary palps 4­ segmented with the last palpomere strongly securiform. Labial palps 3­ segmented. Antennae pubescent equipped with long setae, surpassing the half of elytra and almost reaching the apex, 12­ segmented, inserted almost close to the eyes; scape elongated, stout, not clubshaped; antennomere II short, narrower near the base, about 2.6 times shorter than scape; antennomeres III–IV longer than previous one, stout and slightly enlarged at apex; antennomeres V– VI slightly sturdier and shorter than previous ones, triangular shaped; antennomere VII slightly saucer­shaped and slightly asymmetrical dilated, more transverse than previous ones; antennomere VIII asymmetric, rather elongated, strongly curved and deformed, apex concave; antennomere IX asymmetric, strongly saucer­shaped, thin, strongly transverse; antennomeres X–XII very elongated and filiform, antennomere XI shorter than X and last antennomere which is the longest and has a rounded apex. Pronotum sub­rectangular that does not cover the head, longer than wide, sides straight and finely bordered, anterior margin straight and finely bordered, posterior margin very slightly undulate, surface bulged on the disc equipped with few and very long setae and without punctuation. Scutellum triangular­shaped. Elytra long which covers and surpasses the last abdominal segments, parallel sided and with rounded apex, slightly wider than pronotum, surface with small punctuation and with long setae. Posterior wings semi­transparent, longer than elytra. Sternum elongated and pubescent, ventrites transverse and pubescent, last ventrite apparently very short and transverse, last tergite very broad and emarginate at apex, probably part of edeagus visible with a long and strongly pubescent appendix which is very thin at base and enlarged and rounded at apex. Legs slender, long and pubescent; coxae wide, subsquare; trochanters elongated; femurs cylindrical, straight, sturdier than tibiae; tibiae slender, cylindrical, with an apical spur which is curved and robust, pro­ and mesotibiae shorter than pro­ and mesofemora, metatibiae slightly longer than metafemora. Tarsal formula 5­ 5­ 5; first tarsomere elongated, slightly shorter than the second and third together; second elongated; third tarsomere almost triangular, not bilobed at sides; fourth tarsomere strongly bilobed; fifth tarsomere thin and very elongated; claws simple with an obtuse tooth at base. Female unknown.

Etymology. Named in honor of Thomas Wentzel, husband of the first author (Danuta Wentzel).

Syninclusions. Stellate hairs, botanical remains and air bubbles.

Systematic placement. The last maxillary palpomere securiform, tarsal formula 5­ 5­ 5, elongated elytra, pronotum without lobes and teeth at sides, and the antennae 12­ segmented with some antennomeres saucer­shaped, unequivocally make the new species belong to the subfamily Cantharinae Imhoff, 1856 and to the tribe Cacomorphocerini Fanti & Kupryjanowicz, 2018 ( Brancucci 1980; Ramsdale 2002; Fanti & Kupryjanowicz 2018; Fanti & Pankowski 2019; Poinar & Fanti 2019; Kazantsev & Perkovsky 2020). The new species belongs to the genus Cacomorphocerus Schaufuss, 1892 based on its 12 antennomeres with some of these saucer­shaped and antennomeres 10–12 filiform, tarsomere 3 straight and not bilobed ( Bukejs et al. 2019b).

Remarks. Piece of amber that measures 1.88x 1.2 cm. The inclusion is complete, except for the right metathoracic leg preserved up to part of the third tarsomere. The left side is poorly visible, and therefore also the last antennomeres of the left antenna.

Figures

Fig. 1. Cacomorphocerus thomasiwentzeli sp. nov. in Baltic amber. A: Holotype, lateral view, bar = 1.0 mm; B: Holotype, detail of last abdominal segments, bar = 0.5 mm.

Fig. 2. Cacomorphocerus thomasiwentzeli sp. nov. in Baltic amber. Reconstruction of antenna.