Cantharis (Cantharis) crisantha FANTI & M. G. PANKOWSKI, 2020

Fanti, Fabrizio & Pankowski, Maximilian G., 2020, Two new species of Cantharis Linnaeus, 1758 from Baltic amber, Zootaxa 4878 (3), pp. 401-411 : 402-405

Cantharis (Cantharis) crisantha FANTI & M. G. PANKOWSKI sp. nov.

( Figs. 1–3 )

Description. Adult, winged. Male, based on the long antennae and extruded aedeagus. Body entirely dark brown. Body length: 6.1 mm; elytra 5.0 mm; head and pronotum 1.1 mm, antennae 5.3 mm long.

Head partially covered by pronotum, wide, with scattered long setae. Eyes large, convex, prominent, inserted in the upper-lateral part of the head, interocular dorsal distance about 3.3 times greater than eye diameter ( Figs. 1 , 2B ). Mandibles elongate, slender, falciform, pointed apically, without any tooth. Maxillary palpi 4-segmented, with first palpomere short; second palpomere elongate and robust; third palpomere globular and slightly longer than first; last palpomere slender, elongate, securiform, pointed apically. Labial palp 3-segmented. Antennae 11-segmented, long, not reaching the apex of elytra, filiform, pubescent and adorned with sparse setae; scape short, very robust, club-shaped; antennomere II short, half the length of scape; antennomere III filiform, elongate, about 1.2 times longer than scape; antennomere IV slightly shorter than antennomere III; antennomeres V–VII subequal, slightly shorter and slightly more robust than antennomere IV ( Fig. 2C ); antennomeres VIII–IX longer than antennomere III; antennomere X shorter than previous ones; antennomere XI long, slender, rounded at apex ( Fig. 2C ). Pronotum transverse, almost 2.0 times wider than long, slightly wider than the head, equipped with scattered and long setae, anterior margin strongly rounded, sides rounded, posterior margin almost straight and slightly bordered ( Fig. 2B ), surface flat, anterior corners strongly rounded, posterior corners very slightly pointed. Scutellar shield triangular with rounded apex. Elytra wider than pronotum, elongate, covering and surpassing the last abdominal segment, parallel-sided, equipped with sparse and short setae, rounded at apex, surface smooth without any surface structure, suture and sides not bordered ( Figs. 1A , 2A ). Hind wings totally covered by elytra, infuscate. Sternum subquadrate, with shallow punctures, strongly rounded posteriorly. Abdominal ventrites transverse, slightly pubescent ( Figs. 1B , 3 ). Legs covered with long pubescence, pro- and mesothoracic legs short, posterior pair of legs long; coxae robust and rounded; trochanters elongate with rounded apex; femora cylindrical and only slightly compressed, moderately curved; pro- and mesotibiae as long as pro- and mesofemora or a bit shorter, metatibiae shorter than metafemora, slender, slightly sturdier at apex, cylindrical. Tarsi 5-segmented, equipped with long setae; first tarsomere elongate, robust; second tarsomere shorter than first tarsomere; tarsomere III slightly shorter than second, inconspicuously lobed at sides; tarsomere IV short and strongly bilobed; tarsomere V thin and elongate; claws simple with very small and obtuse basal tooth. Aedeagus visible in its dorsal face (thus the parameres cannot be observed) with large dorsal shield that is emarginate and slightly hollowed at the margin, two elongated lateral sclerites ( Fig. 3 ). Female unknown.

Etymology. The specific epithet “ crisantha ” is an anagram of the genus name Cantharis . Derived from the Latin noun “ chrȳsŏs ” = gold (borrowed from the Ancient Greek χρῡσός / khrūsós) and thus also in reference to the coloration of the amber specimen.

Holotype. Male , adult specimen in a Baltic amber piece: Catalog number MCZ: Ent:PALE-43614, in the Museum of Comparative Zoology ( MCZ) at Harvard University.

Type locality. Open pit mine (“Primorskoje”) in Yantarny (formerly Palmnicken), Baltic Sea Coast, Sambian Peninsula, Kaliningrad Region, Russia.

Type strata. Baltic amber, Eocene, Priabonian, Prussian Formation, “Blue Earth—Blaue Erde” sediment (age 38.0–35.6 million years).

Syninclusions. Stellate hairs, botanical remains, gas vesicles (air bubbles), an ant, and a dipteran (Nematocera: Culicomorpha: Chironomidae ).

Systematic placement. The securiform last maxillary palpomere, laterally rounded pronotum, the filiform 11- segmented antennae, the shape of male genitalia, third bilobed tarsomere, and the simple claws with a basal tooth reliably place the new species in the genus Cantharis and its nominotypical subgenus ( Brancucci 1980; Kazantsev 2018).

Differential diagnosis. In addition to various specimens determined only at the generic level (Fanti 2017), currently seven other species of the genus Cantharis ( Kuśka 1992, 1996; Fanti & Damgaard 2018, 2019; Kazantsev 2018; Kupryjanowicz & Fanti 2019), plus an undetermined specimen close to the living C. nigricans ( Burmeister 1832), are known from Baltic amber. Cantharis (Cyrtomoptila) mikkelsenorum Fanti & Damgaard, 2018 is larger, while C. (s. str.) hoffeinsorum Kazantsev, 2018 and C. (s. str.) borki Fanti & Damgaard, 2019 are smaller, and all have different pronotal shapes compared to Cantharis crisantha sp. nov. In Cantharis (Cyrtomoptila) sucinokotejai ( Kuśka, 1996) , the pronotum is almost square. C. (s. str.) dougi Kupryjanowicz & Fanti, 2019 has a pronotum subrectangular, very transverse with straight lateral margins, while C. (s. str.) sucinonigra Kuśka, 1992 has a smaller head, a widely rounded pronotum, and different lengths of antennomeres II–V. The most similar species to C. crisantha sp. nov. in habitus is C. (s. str.) hanswerneri Kazantsev, 2018 but its antennomeres II–IV have very different lengths and its pronotal anterior margin is less rounded. Other species of Cantharis have been described as compression fossils from Enspel ( Fanti & Poschmann 2019), Rott ( Heyden & Heyden 1866; Fanti & Walker 2019), and Oeningen ( Heer 1847, 1865) in Germany, as well as in Radoboj in Croatia ( Heer 1847). Still others are known from compression fossils from Puy-Saint-Jean in France ( Piton & Théobald 1936) and Randecker Maar in Germany ( Schawaller 1986).

Remarks. The golden yellow amber piece is rectangular and measures approximately 19 x 9 mm. The inclusion is complete and easily visible. The beetle’s legs are curled up, its abdomen is bent, and it has an extruded aedeagus in dorsal view.

Figures

FIGURE 1. Cantharis (Cantharis) crisantha sp. nov. in Baltic amber. A: Holotype, dorsal view, scale bar = 1.0 mm. B: Holotype, ventral view, scale bar = 1.0 mm.

FIGURE 2. Cantharis (Cantharis) crisantha sp. nov. in Baltic amber. A: Holotype, dorsal view (larger details), scale bar = 1.0 mm. B: Holotype, detail of head, pronotum, and scutellar shield, scale bar = 0.5 mm. C: Holotype, detail of right antenna (ventral view), scale bar = 0.5 mm.

FIGURE 3. Cantharis (Cantharis) crisantha sp. nov. in Baltic amber. Holotype, detail of last urites and aedeagus, scale bar = 0.4 mm.