Mantimalthinus bartholini, Fanti & Damgaard, 2019

Fanti, Fabrizio & Damgaard, Anders Leth, 2019, New soldier beetles (Cantharidae) from Baltic, Burmese and Dominican ambers of the Anders Damgaard amber collection, Baltic Journal of Coleopterology 19 (2), pp. 101-125 : 117-118

Mantimalthinus bartholini sp. nov.

( Figs. 15 - 16 )

Holotype. Probably male, in Baltic amber, accession No. ALDC0511 /ALD. Ba.Can. 25

Type locality. Russia: Kaliningrad Region, Sambian Peninsula, Yantarny.

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

Differential diagnosis. The maxillary palpi globular and pointed apically make this specimen clearly belongs to the Subfamily Malthininae Kiesenwetter, 1852 . Mandibles even are not visibles, but the habitus with long elytra and the pronotal shape with the sides narrowed in the middle and the posterior margin highly bordered at the angles, make the species believe closely related to the genus Mantimalthinus Fanti & Castiglione, 2017 . Only a fossil species of this genus is known: Mantimalthinus balticus Fanti & Castiglione, 2017 which differs from M. bartholini sp. nov. by the different length of the antennomeres, by less transverse pronotum and the last ventrite which has the margin elongate apically, where this margin is slightly concave in M. bartholini sp. nov. ( Fanti & Castiglione 2017).

Description. Adult, winged. Probably male on the basis of the the last sternite narrower than last tergite. Brown with black pronotum. Body length: about 4.0 mm; elytra: 3.0 mm.

Head completely exposed, as large as anterior part of pronotum, rounded, with shallow punctation. Eyes convex, round, inserted on the lateral part of the head, inter-ocular dorsal distance about 1.9 times greater than eye diameter. Mandibles not visible. Maxillary palpi 4-segmented with palpomeres of different lengths, and with the last segment globular and pointed. Labial palpi 3-segmented with last palpomere globular and pointed. Antennae filiform, 11-segmented, brown, short, slightly surpassing the humeral zone and not reaching the half of the elytra, strongly pubescent; scape long, club-shaped; antennomere II about 1.25 times shorter than the scape and thickened towards the apex; antennomeres III-IV slightly shorter than antennomere II; antennomeres V –X long and subequal; antennomere XI long, filiform, with rounded apex. Pronotum transverse about 1.6 times (on the basal part) as wide as long, black, narrower than the elytra, surface flat covered with erected pubescence and without evident punctation, front margin bordered and the hind margin strongly bordered in particular at the angles, sides slightly narrowed in the middle, the hind part of the pronotum is wider than the anterior one, corners rounded. Scutellum dark brown - blackish, robust, triangular and rather elongate, with apex truncated. Elytra elongate, completely covering and surpassing the abdomen, with parallel sides and strongly rounded apex, surface strongly wrinkled equipped with long hairs and without traces of ridges. Metathoracic wings well visible, with very few veins. Metasternum subquadrate, pubescent; sternites transverse equipped with hairs and five sternites with extruded vesical (large, gray and spongy), last sternite narrower than last tergite and with apical margin slightly concave. Legs long, with numerous and thick hairs; coxae stout and rounded; trochanters elongate with rounded apex; femora short and slightly enlarged; tibiae cylindrical, longer than femora; tarsal formula 5-5-5, with the first tarsomere 2.0 times longer than second tarsomere, the third tarsomere slightly shorter than second, the fourth strongly bilobed and the fifth elongate and thin; claws simple.

Etymology. In memory of the Danish physician, mathematician and theologian Thomas Bartholin (Malmö - Scania, 20 October 1616 - Copenhagen, 4 December 1680). He theorized that amber had to come from conifers and that it had been hardened in seawater. He was therefore also one of the pioneers of Danish amber research.

Syninclusions. Few debris.

Remarks. The piece is almost flat and very transparent, and has a vaguely triangular shape. Measure 20 x 12 x 4.5 mm. Inclusion is complete, with also the metathoracic wings visible, and with only the mandibles hidden by the legs.

Figures

Fig. 15. Mantimalthinus bartholini sp. nov.ALDC0511/ALD.Ba.Can.25 in Baltic amber. A: Holotype, dorsal view, bar = 1.0 mm; B: Holotype, ventral view, bar = 1.0 mm; C: Holotype, detail of pronotum and scutellar shield, bar = 300 μm; D: Holotype, detail of the elytral apex, bar = 200 μm.

Fig. 16. Mantimalthinus bartholini sp. nov.ALDC0511/ALD.Ba.Can.25 in Baltic amber. A: Holotype, detail of eyes and palpi, bar = 200 μm; B: Holotype, detail of antennae and metasternum, bar = 200 μm; C: Holotype, detail of adbominal segments (arrows show the extruded vesicles), bar = 400 μm; D: Holotype, detail of leg, bar = 100 μm.