Cacomorphocerus madseni, Fanti & Damgaard, 2018

Fanti, Fabrizio & Damgaard, Anders Leth, 2018, Fossil soldier beetles from Baltic amber of the Anders Damgaard amber collection (Coleoptera Cantharidae), Baltic Journal of Coleopterology 18 (1), pp. 1-32 : 4-5

Cacomorphocerus madseni n. sp.

( Figs. 1D - 2 )

Holotype. Male, in Baltic amber, accession No. ALDC0390 /ALD. Ba.Can. 15

Type locality. Russia, Kaliningrad Region, Sambian Peninsula, amber quarry near Yantarny (previously known as Palmnicken).

Type horizon. Middle Eocene (Lutetian) (47.8- 41.2 MY) to Late Eocene (Priabonian) (37.8- 33.9 MY).

Differential diagnosis. Cacomorphocerus madseni n. sp. has the pronotum with deep transversal incision, not present in any other Cacomorphocerus or fossil soldier beetles ( Cacomorphocerus cerambyx Schaufuss, 1892 has the longitudinal incision). It is also characterised by the extremely shorts protibiae and the pronotum with two strong expansions at sides.

Description. Adult, winged, robust and stocky habitus. Male, based on the triangular and narrow last ventrite. Body length 6 mm. Entirely blackish. Head slightly wider than pronotum, rounded, posteriorly covered by pronotum. Eyes roundish, strongly prominent. Maxillary palps 4-segmented with last palpomere securiform. Labial palps 3-segmented with the last segment elongated and slightly globular and pointed. Antennae short, slightly surpassing the humeri, 12-segmented; scape elongated, stout; pedicel extremely short and roundish; antennomeres III-VI stout, slightly saucer-shaped and asymmetrically inflated; antennomeres VII-VIII strongly dilated and saucer-shaped, with antennomere VIII wider than antennomere VII; an ten n omer e IX sligh tly n ar r ower th an an ten n omer e VIII; an ten n omer es X-XII elongated and filiform. Pronotum convex, as wide as elytra, with in the middle a deep and sinuous transversal incision; basal margin straight; apical margin slightly sinuous; sides with two strong denticles - expansions rounded at apex, one near the basal angles and another one just above the median incision; surface with punctation. Scutellum very wide, elongated, with roundish apex. Elytra very long, surpassing the last abdominal segments, parallel-sided, with rounded apex, covered with numerous short setae. Posterior wings completely covered by elytra. Sternum and abdomen pubescent, with last ventrite triangular and very narrow. Legs short, slender, only the posterior long; coxae massive; trochanters triangular, very narrow; femora slightly enlarged fitted with short pubescence; protibiae extremely short, mesoand metatibiae long and cylindrical with pubescence. Tarsi 5-segmented; first tarsomere elongated; second about 2.5 times shorter than first tarsomere; third tarsomere triangular; fourth discoidal with anterior margin straight; fifth elongated and thin; claws simple, not well visible but seemingly with a denticle at base.

Etymology. This new species is named in honour of the Danish novelist Svend Åge Madsen, in recognition of his writings.

Syninclusions. Stellate trichomes, a big air bubble and a few small wood remains.

Remarks. The piece of amber is transparent, roundish drop-shaped and measures 15 x 11 x 5 mm. The legs of the inclusion are present, but some of them are curled up and the right mesotibia is broken and detached almost at the beginning. The head and partially the pronotum are covered by a white emulsion, and the pronotum is also damaged. The last article of the right antenna is missing.

Figures

Fig. 1. ABC: Cacomorphocerus bentifabrici n. sp. in Baltic amber. A: Holotype, dorso-lateral view, bar = 1.0 mm; B: Holotype, detail of head and pronotum, bar = 300 μm; C: Drawing of pronotum, bar = 500 μm; D: Cacomorphocerus madseni n. sp. in Baltic amber. Drawing of pronotum, bar = 500 μm.

Fig. 2. Cacomorphocerus madseni n. sp. in Baltic amber. A: Holotype, dorsal view, bar = 1.0 mm; B: Holotype, ventral view, bar = 1.0 mm; C: Holotype, detail of pronotum, bar = 500 μm.