Malthodes susanbuttsae M. V. PANKOWSKI & FABRIZIO FANTI, 2025

Pankowski, Madeline V., 2025, A remarkable new fossil Malthodes (Coleoptera, Cantharidae, Malthininae) from Baltic amber, Zootaxa 5661 (3), pp. 431-439 : 432-436

Malthodes susanbuttsae M. V. PANKOWSKI & FABRIZIO FANTI sp. nov.

( Figs. 1–3 )

Description. Adult, winged, slender. Male defined on the basis of last urites (both tergites and sternites) strongly modified ( Figs. 1–3 ). Body length: about 4.7 mm (from head to the apex of last sternite); elytra length: 2.0 mm; pronotum length: 0.4 mm; head length: 1.0 mm. Entirely dark brown, elytra without yellow spots at apex.

Head exposed, small, rather rounded, wrinkled, equipped with several short setae and shallow punctation. Eyes large, prominent, convex, rounded, inserted in lateral-upper part of head. Mandibles falciform, very 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, moderately long, slightly surpassing elytra, just reached last tergite; antennomere I elongated, rather robust, club-shaped; antennomere II short, about 2.4 times shorter than antennomere I; antennomere III about 1.4 times longer than antennomere II; antennomeres IV–IX elongated, sub-equal in length and shape, longer than previous one, shorter than scape; antennomere X, slightly shorter than previous ones; antennomere XI elongated, rounded at apex; all antennomeres equipped with several short setae. Pronotum strongly transverse, wider than head, surface irregular (not flat) with very minute punctation and several short setae, sides straight but slightly enlarged anteriorly, anterior margin bordered and slightly rounded, posterior margin straight and strongly bordered, corners rounded. Elytra short, wider than pronotum, smooth, equipped with several setae, parallel-sided (slightly dehiscent posteriorly), rounded at apexes, without apical yellow spots. Hind wings infuscate, noticeably exceeding elytra and last abdominal segments. Legs slender, pubescent; coxae short and robust; trochanters rather robust, short, with rounded apex; femora enlarged, slightly curved; tibiae cylindrical and thin, pro- and mesotibiae shorter than pro- and mesofemora, metatibiae longer than metafemora. Tarsi 5-segmented, pubescent; tarsomere I elongated; tarsomere II shorter than tarsomere I; tarsomere III shorter than tarsomere II; tarsomere IV strongly bilobed with lobes rounded at apex; tarsomere V thin, elongated, slightly curved; claws simple without tooth. Metasternum rectangular with posterior margin straight. Sternites transverse and pubescent, three abdominal segments with an extruded cuticular vesicle. Last tergite (tg10) slightly modified, equipped with a few long setae, robust, lobed, triangular-shaped, contrasts with strongly modified last sternite (st9), which in basal part is elongated, broad, and flat, and at apex (laterally) bifurcated with these parts strongly pubescent and thin, cylindrical and above all exceptionally long and curved.

Etymology. Species named after Dr. Susan Butts, Director of Collections & Research at the Yale Peabody Museum, for her unwavering dedication to studying and preserving our prehistoric past.

Holotype. Male, in Baltic amber, deposited under accession number YPM IP.463895 at the Yale Peabody Museum in New Haven, Connecticut, USA (ex coll. Jonas Damzen: JDC-5976).

Type locality and type horizon. Yantarny mine, Sambian Peninsula , Kaliningrad Region, Russia. Middle Eocene: Bartonian-Priabonian (41.0–33.9 Mya).

Syninclusions. An Araneae ( YPM IP.463896 at the Yale Peabody Museum), an Empididae ( YPM IP.463897), a Dolicophodidae ( YPM IP.463898), an unidentified Diptera ( YPM IP.463899), air bubbles, and botanical remains.

Systematic placement. The pronotal shape, short elytra, the last maxillary palpomere globular and distally pointed, and the last abdominal segments strongly modified place this species in the genus Malthodes Kiesenwetter, 1852 and its nominotypical subgenus ( Wittmer 1970; Brancucci 1980; Liberti 2011; Kupryjanowicz & Fanti 2019).

Differential diagnosis. The exceptionally distinctive shapes of the last abdominal segments of M. susanbuttsae sp. nov. are not observed in any fossil Malthodes ( Fanti 2017, 2025a). Slightly similar forms of the last abdominal segments can be found in just a few Malthodes species living in the western Palearctic and North America ( Fender 1951; Kaszab 1955a, 1955b; Wittmer 1970, 1992; Liberti 2011, 2015, 2016, 2017, 2021, 2023; Liberti & Poggi 2018; Diéguez Fernández 2021; Kazantsev 2021, 2024), such as Malthodes flexuosus Fender, 1951 , found in Oregon in the United States ( Fender 1951); and Malthodes forcipifer (Kiesenwetter, 1852) , observed in Spain, Portugal, and France ( Diéguez Fernández 2021). However, these last abdominal segments do not closely resemble those of M. susanbuttsae sp. nov.

Remarks. The yellowish amber piece measures approximately 63x23x 8 mm, and weighs 6.3 grams. The inclusion is complete. Female of the new species is unknown.

Figures

FIGURE 1. Malthodes (Malthodes) susanbuttsae sp. nov. holotype, in Baltic amber.A, habitus, dorsal view; B, habitus, ventral view. Scale bars = 1.0 mm.

FIGURE 2. Malthodes (Malthodes) susanbuttsae sp. nov. holotype, in Baltic amber. A, detail of last tergites; B, detail of last sternites. Scale bars = 0.5 mm.

FIGURE 3. Malthodes (Malthodes) susanbuttsae sp. nov. holotype, in Baltic amber. A, reconstruction of last abdominal segments, ventral view; B, reconstruction of last abdominal segments, dorsal view.