Silis (Silis) curleri FANTI & M. G. PANKOWSKI, 2021

Fanti, Fabrizio & Pankowski, Maximilian G., 2021, Two new species of soldier beetles (Coleoptera, Cantharidae), the first from the tribe Silini in Dominican amber, Zootaxa 4996 (1), pp. 163-170 : 166-168

Silis (Silis) curleri FANTI & M. G. PANKOWSKI sp. nov.

( Figs. 3–4 )

Description. Adult. Male winged, with elongated lateral lobes and spines of pronotum. Head, elytra and antennae brown-dark brown; pronotum and legs brown. Body length: about 6.4 mm; elytra: 5.0 mm.

Head large, transverse, narrower than pronotum, narrow and rounded behind the eyes, almost smooth and finely pubescent, partially covered by pronotum. Eyes roundish and strongly protruded, convex, inserted in the upper and lateral part of the head occupying the major part of the sides. Mandibles falciform, slender. Maxillary palpi 4-segmented, palpomeres unequal in length with the last palpomere strongly securiform. Labial palps 3-segmented. Antennae inserted in the frons and away from the eyes, long, almost reaching the elytral apex, 11-segmented, filiform, all antennomeres wrinkled and covered with sparce setae; scape elongate, club-shaped; antennomere II (pedicel) short, approximately 1.2 times shorter than scape, robust; antennomere III very slightly shorter than second; antennomeres IV-IX filiform, longer than antennomere III and approximately as long as scape; antennomere XI filiform, oblong, with rounded apex. Pronotum transverse, surface almost flat, with long, erect setae and with small rugosity; anterior margin strongly rounded, posterior margin almost straight, sides with two lobes, anterior lobe elongate and arcuate and thinner apically with the tip rounded, posterior lobe very broad, spine inserted under the posterior lobe and curved and very long and thin apically, groove between the two lobes narrow and rounded. Scutellum triangular-shaped with truncated or slightly rounded apex. Elytra almost as wide as pronotum, elongate, leaving the last abdominal segment uncovered, parallel-sided, with slightly wrinkled microsculpture and semi-erect setae, apex strongly rounded. Posterior wings almost completely covered by elytra. Metasternum sub-quadrate with posterior margin almost straight; abdominal segments robust, transverse and pubescent; last tergite broad with a central groove; last ventrite elongate, triangular-shaped and deeply divided forming two halves, with apex rounded. Legs long, slender and pubescent; coxae short and robust; trochanters elongate with rounded apex; femora enlarged and almost straight; tibiae cylindrical, protibiae shorter than profemora, mesotibiae as long as mesofemora, metatibiae slightly longer than metafemora. Tarsal formula 5-5-5; first tarsomere robust, elongate; second tarsomere shorter than first; third tarsomere triangular-shaped; fourth tarsomere deeply bilobed at the sides; fifth tarsomere elongate, slender and curved; claws simple without basal tooth. Female unknown.

Etymology. Species named after Dr. Gregory R. Curler for his numerous contributions to entomology and his great generosity in sharing his knowledge with students.

Holotype. Male , adult specimen in a Dominican amber piece: Catalog number MCZ: Ent:PALE-43617, in the Museum of Comparative Zoology ( MCZ) at Harvard University.

Type locality. The Cordillera Septentrional mountain range in the Dominican Republic, from the “Montearachi” mine in the “Los Cacaos” mining area.

Type horizon. Late Early/Middle Miocene; 15–20 million years ago (mya), probably close to 16 mya. La Toca Formation.

Syninclusions. Detritus and plant remains, air bubbles, a spider, some unidentified dipterans and a coleopteran.

Systematic placement. The securiform last maxillary palpomere, the pronotum with lateral lobes/apophyses, the abdomen with only eight visible urites, the elongated elytra, and meso- and metatarsal claws simple and without basal tooth place this new species in the subfamily Silinae and the genus Silis ( Brancucci 1980; Ramsdale 2002; Constantin 2009, 2017). The lateral margin of the pronotum without minute glandular tuberosity also places Silis curleri sp. nov. in the nominotypical subgenus Silis ( Constantin 2009) .

Differential diagnosis. A living species present in Haiti, Silis debililimbata Wittmer, 1991 , appears extremely similar to Silis curleri sp. nov., both for its similar body size and the shape of its pronotum ( Wittmer 1991a). Silis curleri sp. nov., however, has a slightly longer and thinner anterior lobe, and a slightly shorter, stockier and more curved posterior spine, as well as a broader concavity at the posterior margin near the spine. The only Silis found so far in Miocene deposits is Silis chiapasensis Wittmer, 1963 from Mexican (Chiapas) amber ( Wittmer 1963). It differs from the new species by its more transverse pronotum and the different shape of its lobes and spines, as well as its smaller body size.

Remarks. The amber piece is transparent, measures 46.4 x 29.2 x 13.8 mm and weighs 10.558 grams. The inclusion is easily visible, and only the beetle’s right antenna is missing.

Figures

FIGURE 3. Silis (Silis) curleri sp. nov. in Dominican amber. A: Holotype, dorsal view, scale bar = 1.0 mm. B: Holotype, dorsal view (black/white), scale bar = 1.0 mm.

FIGURE 4. Silis (Silis) curleri sp. nov. in Dominican amber. AB: Holotype, ventral views, scale bars = 1.0 mm. C: Holotype, detail of head, pronotum, and elytra (humeral zone), scale bar = 1.0 mm. D: Holotype, detail of head, pronotum (ventral view), and metasternum, scale bar = 1.0 mm.