Malthinus (Malthinus) pauljohnsoni, PANKOWSKI & Fanti, 2023

PANKOWSKI, MAXIMILIAN G. & Fanti, FABRIZIO FANTI, 2023, Six new species of fossil soldier beetles (Coleoptera: Cantharidae) from Eocene Baltic amber, Palaeoentomology 6 (3), pp. 300-312 : 306

Malthinus (Malthinus) pauljohnsoni sp. nov.

( Fig. 5 )

Holotype. Female , inclusion in Baltic amber, housed at the Smithsonian National Museum of Natural History, USNM PAL 787826 .

Syninclusions: Botanical fragments, stellate hairs, small air bubbles and a Diptera (with eggs).

Etymology. Species named in honor of Dr. Paul Johnson, a professor at South Dakota State University who is always happy to provide his invaluable expertise on beetle taxonomy.

Diagnosis. This species belongs to the genus Malthinus based on its globular and distally pointed last maxillary palpomere, the short elytra, head restricted behind the eyes and the elytra with impressed punctuation.

Only three fossil species of Malthinus have been described so far, all from Baltic amber ( Kuśka & Kania, 2010; Fanti & Damgaard, 2018; Pankowski & Fanti, 2022). Malthinus rifbjergi Fanti & Damgaard, 2018 and Malthinus danieli Kuśka & Kania, 2010 are the most similar to the new species described here, but they have the pronotum only narrower anteriorly ( Kuśka & Kania, 2010; Fanti & Damgaard, 2018), where in Malthinus pauljohnsoni sp. nov. the pronotum is widely expanded before the posterior corners.

Locality and horizon. Amber mine in the Yantarny settlement, Sambian Peninsula, Kaliningrad region, Russia. Middle Eocene (Lutetian) (47.8–41.2 Ma) to late Eocene (Priabonian) (37.8–33.9 Ma).

Description. Female, defined on the basis of the short antennae and wide and rounded last sternite. Body length: about 4.9 mm. Body entirely dark brown without yellow spots on elytra.

Adult, alate, slender. Head completely exposed, strongly narrowed behind eyes, very strongly wrinkled, with deep and wide punctation, interocular dorsal distance about 2.5–2.6 times greater than eye diameter. Eyes large, convex, rounded, located in the upper lateral part of head. Mandibles falciform, elongate, thin. Maxillary palpi 4- segmented, with last palpomere globular and apically pointed. Labial palpi 3-segmented, with last palpomere globular and apically pointed. Antennae filiform, 11- segmented, short, surpassing half of elytra but not reaching the elytral apex; antennomere I elongate, slightly club-shaped; antennomere II about 2.1 times shorter than antennomere I; antennomeres III–IX subequal, very slightly longer and slender than antennomere II; antennomere X very slightly shorter than previous ones; antennomere XI elongate, very slightly pointed; all antennomeres covered by short setae. Pronotum longer than wide, narrower than head, slightly punctate, equipped with short setae, anterior margin straight and strongly bordered, posterior margin undulate, sides with a wide expansion before the posterior corners.Scutellum wide with truncate apex, enlarged in the middle. Elytra short, revealing three and a half abdominal segments uncovered, wider than pronotum, covered with deep punctation (smaller punctation close to the elytral apex) in rows and some setae, parallel-sided, rounded at apex. Hind wings slightly infuscate, clearly exceeding elytra and slightly exceeding last abdominal segment. Metasternum with straight posterior margin, covered with dispersed and short setae and very shallow punctation. Sternites transverse with shallow punctation. Last tergite and last sternite wide and rounded. Legs slender, pubescent; coxae short, stout; trochanters elongate with rounded apex; femora enlarged, rather straight; tibiae cylindrical and thin, equipped with apical spurs, pro- and mesotibiae shorter than pro- and mesofemora, metatibiae longer than metafemora. Tarsomere I thin, elongate; tarsomere II about 1.8 times shorter than tarsomere I; tarsomere III very short, rounded; tarsomere IV strongly bilobed; tarsomere V elongate, slightly curved, slender; claws simple without tooth. Male unknown.

Remarks. The yellow amber piece measures approximately 18 × 13 × 10 mm. The inclusion is complete. The last tergites and ventral part of the head are covered with white emulsion.

Figures

FIGURE 5. Malthinus (Malthinus) pauljohnsoni sp. nov. in Baltic amber. Holotype (USNM PAL 787826). A, Dorsal view. B, Ventral view. Scale bars = 1.0 mm.