Malthodes caenozoicus, Fanti & Vitali, 2017

Fanti, Fabrizio & Vitali, Francesco, 2017, Key to fossil Malthininae, with description of two new species in Baltic amber (Coleoptera Cantharidae), Baltic Journal of Coleopterology 17 (1), pp. 19-27 : 19-27

Malthodes caenozoicus n. sp.

( Figs. 1 - 3 )

Holotype. Male. Baltic amber from Lithuania, ex coll. W. Lewita G 109, coll. F. Vitali; age: Early Oligocene.

The specimen is included in a pentagonal piece of amber measuring approximately 1.5 cm at each side and 1 cm high. In addition to the beetle, the sample includes some “stellate hairs”, usually identified as trichomes covering oak inflorescences. Considering the deformation of the holotype, the amber was evidently autoclaved (C. Gröhn in litt.).

Differential diagnosis. This new species is similar to the extant European Malthodes brevicollis (Paykull, 1798) , which shows analogous small size, dark coloration, short antennae and similar terminalia. Malthodes caenozoicus n. sp. differs from M. brevicollis in the not-incised urosternite IX and in the shorter, trapezoidal, apically slightly incised and not-enlarged posteriorly urotergite X. Additionally, M. brevicollis shows longer elytra.

Description. Male. Body length: 1.8 mm; minute, elongated, entirely pitch black; antennae and elytra relatively short.

Head rounded, posteriorly moderately constricted; eyes prominent; temples twice as long as upper side of the eyes. Last maxillary palpomere globular and apically pointed.

Antennae 11-segmented, short, posteriorly hardly surpassing the metafemora, almost moniliform; scape elongate, surpassing the eyes for half of its length; antennomeres II-X subequal, one-half as long as scape; antennomere XI one-third longer than previous ones. Antennomere proportions according to the formula: 2.8: 1.4: 1.3: 1.4: 1.4: 1.4: 1.4: 1.4: 1.4: 1.4: 2.0.

Pronotum cordiform, hardly as wide as the head, apically rounded; basal angles straight.

Elytra as wide as the head at base, short (1.75 times as long as wide at base), reaching the metafemora posteriorly, apically constricted, acute at apex. Hind wings fully developed.

Legs typical of the genus; tarsomere I as long as tarsomeres II - IV together; tarsomere IV bilobed (plantar pad); tarsomere V thin and longer than III - IV, claws simple.

Key to fossil Malthininae , with description of two new species in Baltic amber ( Coleoptera Cantharidae )

Abdomen elongate; tergite VIII subcylindrical, one-third as wide and one-half as long as VII; tergite IX not clearly visible but elongate lobe-shaped; tergite X trapezoidal, posteriorly enlarged, covered with long pubescence; sternite IX barely elongate, large (lobe-shaped) and not apically incised, covered with long pubescence. A long and thin urophysis, covered with long pubescence, is present at each side of abdominal segment VIII, surpassing the tergite IX.

Etymology. The specific name is derived from Latin “caenozoicus ” = Caenozoic, by reference to the age of the species.

Figures

Fig. 1. Malthodes caenozoicus n. sp., Holotype, dorsal side.

Fig. 2. Malthodes caenozoicus n. sp., Holotype, dorsal side, real colours of the species.

Fig. 3. Malthodes caenozoicus n. sp., reconstruction