Malthodes (Malthodes) markpankowskii M. G. PANKOWSKI & FANTI, 2022

Pankowski, Maximilian G. & Fanti, Fabrizio, 2022, Two new fossil species of soldier beetles (Coleoptera, Cantharidae, Malthininae) from Baltic amber, Zootaxa 5165 (4), pp. 548-556 : 551-553

Malthodes (Malthodes) markpankowskii M. G. PANKOWSKI & FANTI sp. nov.

( Figs. 3–4 )

Description. Adult, winged, male defined on the basis of the last urites strongly modified. Body length: 4.0 mm. Entirely blackish-dark brown without yellow spots on elytra.

Head exposed, wide, rounded, covered by short setae. Eyes large, very prominent, convex, rounded, inserted in the lateral-upper part of head. Mandibles falciform, elongated. Maxillary palpi 4-segmented, with last palpomere globular and distally pointed. Labial palpi 3-segmented, with last palpomere globular and distally pointed. Antennae filiform, 11-segmented, relatively short as they only reach the apex of elytra and about half of abdomen; antennomere I elongated, slightly club-shaped (enlarged from the middle to the apex); antennomere II about 2.0 times shorter than antennomere I; antennomere III about 1.1 times longer than antennomere II; antennomeres IV–IX subequal in length, longer than antennomere III; antennomere X about 1.4 times shorter than previous ones; antennomere XI elongated, rounded at apex; all antennomeres covered by several long setae. Pronotum strongly transverse (approximately one third wider than long), as wide as head, surface almost flat and barely punctate (shallow punctation) with many short setae, sides straight and strongly bordered, posterior and anterior margin strongly bordered and very slightly enlarged/curved in the middle. Elytra short (revealing four tergites uncovered), wider than pronotum, covered with shallow punctation and several erect setae, parallel-sided, strongly rounded at apexes. Hind wings infuscate, exceeding the elytra and partially covering penultimate tergite but not the last one. Legs slender, pubescent; coxae short, stout; trochanters elongated with rounded apex; femora enlarged, slightly curved; tibiae cylindrical and thin, pro- and mesotibiae shorter than pro- and mesofemora, metatibiae as long as metafemora. Tarsi 5-segmented, pubescent; tarsomere I thin, elongated; tarsomere II shorter than tarsomere I; tarsomere III shorter than second; tarsomere IV strongly bilobed; tarsomere V elongated, slightly curved, slender; claws simple without tooth. Metasternum with rounded posterior margin, covered with many dispersed, short setae. Sternites transverse and pubescent. Penultimate tergite (tg9) wide, subrectangular; last tergite (tg10) narrower than penultimate tergite, elongated, with apical margin rather deeply concave; last sternite (st9) very elongated, as narrow as last tergite, apically almost straight (very slightly emarginate). Aedeagus not visible. Female unknown.

Etymology. Species named after Mark S. Pankowski, the big-hearted father of the first author.

Holotype. Male , inclusion in Baltic amber, housed at the Smithsonian National Museum of Natural History, USA, under catalog No. 775571.

Type locality. Amber mine in the Yantarny settlement, Sambian Peninsula, Kaliningrad Region, Russia.

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

Syninclusions. Many stellate hairs, detritus, botanical fragments and air bubbles.

Systematic placement. This new, extinct species clearly belongs to the subfamily Malthininae based on its last maxillary palpomere that is globular and pointed distally. Its rounded head behind eyes, filiform antennae and strongly modified terminalia place the new species in the genus Malthodes .

Differential diagnosis. No sister group of Malthodes markpankowskii sp. nov. has been found living in the Baltic region or Central Europe, and no other fossil species of Malthodes has this combination of characters (in particular the shape of the terminalia) shown by Malthodes markpankowskii sp. nov. One fossil species that is vaguely similar is Malthodes neumanni Fanti, 2019 from Bitterfeld amber. It differs by the shorter last sternite (st9) with a more concave anterior margin ( Fanti 2019), and by its shorter last tergite (tg10). The other slightly similar species is Malthodes meriae Fanti, 2018 from Baltic amber. Compared with the new species described here, M. meriae has a much smaller and shorter last tergite, as well as a last sternite with a more concave anterior margin (Fanti 2018).

Remarks. The yellow rectangular amber piece measures approximately 26x13x 4 mm and weighs 1.2 grams. The inclusion is complete and clearly visible except for small areas around the head.

Figures

FIGURE 3. Malthodes (Malthodes) markpankowskii sp. nov. A: Holotype, habitus, dorsal view, scale bar = 0.5 mm. B: Holotype, habitus, detail of metasternum, scale bar = 0.2 mm. C: Holotype, habitus, ventral view, scale bar = 1.0 mm. D: Holotype, habitus, ventral view (detail), scale bar = 0.5 mm.

FIGURE 4. Malthodes (Malthodes) markpankowskii sp. nov. A: Holotype, habitus, detail of last abdominal segments (ventral view), scale bar = 0.1 mm. B: Reconstruction of last abdominal segments, scale bar = 0.1 mm. Illustration by Dr. Carly Tribull.