A new Malthinus (Coleoptera: Cantharidae: Malthininae) adds to the unrivaled diversity of arthropods found in Eocene Baltic amber Author Pankowski, Madeline V. text Zootaxa 2024 2024-07-18 5481 4 483 489 http://dx.doi.org/10.11646/zootaxa.5481.4.7 journal article 10.11646/zootaxa.5481.4.7 1175-5326 A8D23C50-1556-4A25-94D6-08703F131643 Malthinus fabriziofantii M. V. PANKOWSKI sp. nov. ( Figs. 1–3 ) Description. Adult, winged, slender, female defined on the basis of the last sternite wide and not triangular in shape. Total length: about 2.9 mm . Antennae: about 1.8 mm . Entirely dark brown with elytra blackish and without yellow spot at apices. Head almost completely exposed, strongly narrowed behind eyes, very strongly wrinkled, with deep and very wide punctation, interocular dorsal distance about 1.9–2.0 times greater than eye diameter. Eyes rather large, convex, perfectly rounded, located in the upper lateral part of head. Mandibles falciform, elongate. 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, very short, approximately reaching half of elytra and anterior margin of second abdominal segment; antennomere I extremely elongate, very slightly club-shaped (slightly enlarged from middle to apex); antennomere II elongated, thin, about 1.8–1.9 times shorter than antennomere I; antennomere III as long as antennomere II, thin; antennomeres IV–V sub-equal, longer than previous one; antennomeres VI–VII slightly shorter than previous ones; antennomeres VIII–X shorter than previous ones; antennomere XI elongate, thin, rounded at apex; all antennomeres covered by short setae. Pronotum slightly longer than wide, narrower than head, slightly punctate, equipped with sparse setae, anterior margin straight and bordered, posterior margin straight, sides straight from anterior margin to middle part, sides with a small and rounded expansion after the middle part and slightly restricted near the posterior corners, anterior corners rounded, surface flat. Scutellum triangular shaped. Elytra rather long, revealing last abdominal segment and major part of penultimate segment, wider than pronotum, covered with deep punctation in rows and some setae, parallel-sided, rounded at apex. Hind wings infuscate, clearly exceeding elytra and last abdominal segment. Metasternum with rounded posterior margin, covered with dispersed and short setae and punctation. Sternites transverse, wide, with shallow punctation. Last tergite slightly broader than last sternite, which is wide and rounded. Legs slender, pubescent; coxae elongate, stout; trochanters elongate with rounded apex; femora enlarged, rather straight; tibiae cylindrical and thin, equipped with apical spurs, shorter than femora. Tarsomere I thin, elongate; tarsomere II shorter than tarsomere I; tarsomere III short, triangular; tarsomere IV bilobed; tarsomere V elongate, strongly curved, slender; claws simple without tooth. FIGURE 1. Malthinus fabriziofantii sp. nov. in Baltic amber. A: amber piece with inclusions, scale bar = 5 mm; B: Holotype, dorso-lateral view, scale bar = 0.5 mm. FIGURE 2. Malthinus fabriziofantii sp. nov. in Baltic amber. Holotype, dorso-lateral view, macro shot, scale bar = 0.5 mm. Etymology. The species is named after Fabrizio Fanti, an independent researcher in Italy who has devoted his life to the study of Cantharidae and related beetles. Holotype . Female , inclusion in Baltic amber, deposited in the Museum of Comparative Zoology ( MCZ ) with catalog number: MCZ :Ent:PALE-45886. Type locality. Open pit mine (“Primorskoje”) in Yantarny (formerly Palmnicken), Baltic Sea Coast, Sambian Peninsula, Kaliningrad Region , Russia . Type horizon. Baltic amber, late Eocene, Priabonian, Prussian Formation (37.7 ± 3.0 Ma). Syninclusions. Botanical remains, stellate hairs, air bubbles, a dagger fly ( Empididae ). Systematic placement. The short elytra, the head wrinkled and triangular behind the eyes, small body size, the last maxillary palpomere globular and distally pointed, the elytra with impressed punctuation, and the last abdominal segments not modified clearly place this species in the genus Malthinus Latreille, 1805 ( Brancucci 1980 ). Differential diagnosis. Malthinus fabriziofantii sp. nov. is easily recognizable by its pronotum that is elongated and slightly restricted at the posterior corners. It can be distinguished from similar species based on the pronotum of each: In Malthinus danieli Kuśka & Kania, 2010 and Malthinus rifbjergi Fanti & Damgaard, 2018 the pronotum is enlarged posteriorly; in Malthinus amicitiae Fanti & Vitali, 2023 the pronotum is rectangular with straight sides; in Malthinus masoni M. G. Pankowski & Fanti, 2022 the pronotum is as wide as long and its sides are straight; in Malthinus karenpankowskiae M. G. Pankowski & Fanti, 2023 the pronotum is strongly transverse with straight sides; and in Malthinus pauljohnsoni M. G. Pankowski & Fanti, 2023 the pronotum is widely expanded at the sides before the posterior corners ( Kuśka & Kania 2010 ; Fanti & Damgaard 2018 ; Pankowski & Fanti 2022 , 2023 ; Fanti & Vitali 2023 ). Remarks. The yellow amber piece measures approximately 16 x 13 x 4 mm , and weighs 0.5 grams after preparation. The inclusion is complete. The male of this species is currently unknown.