Malthodes (Malthodes) maximiliani FANTI & M. V. PANKOWSKI, 2024

Fanti, Fabrizio & Pankowski, Madeline V., 2024, A new species of Eocene fossil Malthodes (Coleoptera: Cantharidae) with a rarely observed aedeagus, Zootaxa 5424 (3), pp. 377-382 : 378-379

Malthodes (Malthodes) maximiliani FANTI & M. V. PANKOWSKI sp. nov.

( Figs. 1–2 )

Description. Adult, winged, male defined on the basis of the last urites strongly modified. Body length: about 2.0 mm (the body is moderately bent). Entirely blackish-dark brown without yellow spots on elytra.

Head exposed, elongated, covered by short setae and shallow punctation. Eyes large, very prominent, convex, rounded, inserted in the lateral-upper part of head. Mandibles falciform, elongated. Maxillary palpi 4-segmented, with last palpomere robust, globular, and distally pointed. Labial palpi 3-segmented, with last palpomere globular and distally pointed. Antennae filiform, 11-segmented, relatively long surpassing the apex of elytra and approximately reaching the sixth-seventh tergite; antennomere I elongated, robust, club-shaped (enlarged from the middle to the apex); antennomere II elongated, rather thin, about 1.6–1.7 times shorter than antennomere I; antennomere III moderately more robust and slightly shorter than antennomere II; antennomere IV elongated, enlarged apically, the longest except scape and last antennomere; antennomeres V–VIII subequal in length (antennomere VI very slightly shorter), shorter than previous one; antennomeres IX–X slightly shorter than previous ones; antennomere XI elongated, rounded at apex; all antennomeres have several long setae. Pronotum transverse, narrower than head, surface almost flat with shallow punctation and short setae, sides straight and bordered, posterior and anterior margins rather bordered, corners rounded. Elytra short (revealing five tergites completely uncovered plus one uncovered in part), wider than pronotum, covered with shallow punctation and several erect setae, parallel-sided, strongly rounded at apexes, without apical yellow spots. Hind wings infuscate, exceeding the elytra and last abdominal segments. Legs slender, pubescent; coxae elongated and stout; trochanters elongated with rounded apex; femora enlarged, curved; tibiae cylindrical and thin, pro- and mesotibiae slightly shorter than pro- and mesofemora, metatibiae approximately 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 with lobes rounded at apex; tarsomere V elongated, slightly curved, slender; claws simple without tooth. Metasternum with rounded posterior margin, covered with many dispersed setae. Sternites transverse and pubescent. Penultimate tergite (tg9) elongated, rather wide with sides very slightly bent and enlarged apically; last tergite (tg10) narrower than penultimate tergite, short, in a small lobe shape rounded apically; last sternite (st9) with an elongated lobe shape (thinner from middle to apex), apically rounded and therefore without emargination-concavity. Aedeagus partially visible with parameres that are very long, thin but globular and robust apically. Female unknown.

Etymology. The species is named after Maximilian G. Pankowski, the second author’s brother, friend, and partner in paleontological projects.

Holotype. Male , inclusion in Baltic amber, deposited in the Museum of Comparative Zoology ( MCZ) with catalog number MCZ:Ent:PALE-45868.

Type locality. Gdańsk area, Mierzeja Wiślana (Wisła River estuary area), Poland.

Type horizon. Middle Eocene: Bartonian-Priabonian (45.0–38.0 Mya).

Syninclusions. Air bubbles, botanical fragments, and an insect antenna.

Systematic placement. The pronotal shape, short elytra, the last maxillary palpomere globular and distally pointed, and the last adominal segments modified place this species in the genus Malthodes Kiesenwetter, 1852 and its nominotypical subgenus. It is distinguishable from the fossil subgenus Libertimalthodes Kupryjanowicz & Fanti, 2019 , which shows long elytra covering and surpassing the last abdominal segments, and features a very large aedeagus and a last sternite that is little modified (Fanti 2019; Kupryjanowicz & Fanti 2019; Pankowski & Fanti 2023).

Differential diagnosis. The species most similar to Malthodes maximiliani sp. nov. are M. neumanni Fanti, 2019 from Bitterfeld amber, and the taxa M. nublar Kupryjanowicz & Fanti, 2019 and M. kotejai Kuśka & Kupryjanowicz, 2005 from Baltic amber ( Kuśka & Kupryjanowicz 2005; Fanti 2019b; Kupryjanowicz & Fanti 2019). However, these three species have last tergites that differ from the new species. In addition, the last sternite (st9) of these species is elongated but with a slightly emarginated-concave apex, whereas in the new species the apex of st9 is straight and obtuse.

Remarks. The yellow amber piece measures approximately 6x5x 2 mm and weighs 0.1 grams after preparation. The inclusion is complete.

Figures

FIGURE 1. Malthodes (Malthodes) maximiliani sp. nov. holotype, in Baltic amber. A, ventral view; B, lateral view; C, detail of antenna; D, detail of last abdominal segments (ventro-lateral view).

FIGURE 2. Malthodes (Malthodes) maximiliani sp. nov. in Baltic amber. Reconstruction of last abdominal segments.