Silis (Silis) lombardii, Parisi & Fanti, 2019

Parisi, Francesco & Fanti, Fabrizio, 2019, On the first Silis Charpentier, 1825 from Baltic amber (Coleoptera, Cantharidae), Fossil Record 22 (2), pp. 119-123 : 120-122

Silis (Silis) lombardii sp. nov.

( Figs. 1–3 )

Description

Adult, winged, male-defined on the basis of the long antennae and elongate lateral lobes of the pronotum. Body length: 5.2 mm, elytra: 3.9 mm, antennae: around 3.2 mm. Entirely dark brown.

Head large, as wide as pronotum, slightly rugose, little exposed being partially covered by pronotum. Eyes elliptical and protruded, inserted in the upper and lateral part of the head. Maxillary palpi 4-segmented, unequal in length with the last palpomere very elongate and securiform. Labial palps 3-segmented with the last palpomere securiform. Antennae inserted near the eyes, just reaching the metafemora, 11-segmented, filiform, all antennomeres covered with small setae; scape elongate and enlarged, clubshaped; antennomere II (pedicel) extremely short and globular; antennomeres III–IV longer than antennomere II, robust; antennomere V slightly longer than antennomeres III–IV; antennomeres VI –IX slender and longer than antennomere V; antennomere X slightly shorter than antennomeres VI – IX; antennomere XI filiform, oblong with rounded apex. Pronotum slightly elongate, surface undulating with concavities and small setae and punctuation; apical margin convex; sides posteriorly expanding, with two elongated and apically pointed long processes: the posterior processes are sinuous and with a small basal acute tooth and the anterior ones are slender and straight. Scutellum triangular. Elytra wider than pronotum with slightly rugose microsculpture and some setae; elongate and covering the last abdominal segments; enlarged at humeri and narrow in the middle; apex strongly rounded. Posterior wings almost completely covered by elytra. Metasternum very elongate with rounded posterior margin, abdominal segments transverse and rugose. Legs long, slender and pubescent; coxae short and robust; trochanters elongate and triangular-shaped with rounded apex; femora enlarged and slightly curved; tibiae cylindrical, shorter than femora, with an apical spur. Tarsal formula 5-5-5; first tarsomere elongate and slightly enlarged apically; second shorter than first; third tarsomere triangular and shorter than tarsomere II; fourth tarsomere deeply bilobed at sides; fifth tarsomere very elongate, slender, flat and curved; proclaws with an obtuse basal tooth, meso- and metaclaws simple without basal tooth. Female unknown, sexual dimorphism is supposed.

Etymology

Named in honour of Fabio Lombardi ( Department of Agricultural Science , Mediterranea University of Reggio Calabria, Italy), dear friend and colleague of the first author.

Holotype

Male, in Baltic amber, deposited at the University of Molise (Unimol) with accession no. Unimol AAA003FP.

Type locality

Yantarny mine, Sambian Peninsula, Kaliningrad region, Russia.

Type horizon

Middle Eocene (Lutetian) (47.8–41.2 Myr) to Late Eocene (Priabonian) (37.8–33.9 Myr).

Syninclusions

Air bubbles and debris (botanical remains).

Remarks

The amber piece is flat and elongate and measures approximately 18 mm × 6–8 mm. The inclusion is complete and well visible. The specimen is crumpled but not damaged.

Systematic placement

Maxillary palpi sub-equal in length with last palpomere securiform, elytra elongated, abdomen with only eight visible urites, protarsal claws with small tooth, meso- and metatarsal claws simple, and pronotum laterally with two long lobes in each part clearly make this new species belonging to the subfamily Silinae and to the genus Silis ( Brancucci, 1980; Constantin, 2010, 2017).

Differential diagnosis

Silis lombardii sp. nov. differs from S. chiapasensis Wittmer, 1963 (Mexican Chiapas amber) in a slightly larger size, darker colour, and different shape of pronotum and lateral processes ( Wittmer, 1963). Silis lombardii sp. nov. differs from the extant S. ruficollis in the body colour ( S. ruficollis is black with red pronotum), the smaller size (5.2 instead of 6–7.5 mm in S. ruficollis ) and in the more elongate lateral lobes of the pronotum.

Figures

Figure 1. Silis (Silis) lombardii sp. nov. in Baltic amber, holotype. (a) Dorsal view, scale bar = 1.0 mm. (b) Ventral view, scale bar = 1.0mm.

Figure 2. Silis (Silis) lombardii sp. nov. in Baltic amber, holotype. (a) Detail of pronotum (arrow), scale bar = 0.4 mm. (b) Detail of right antenna, scale bar = 0.4 mm.

Figure 3. Silis (Silis) lombardii sp. nov. in Baltic amber, holotype. (a) Detail of pronotum (ventral view), elytra, legs and antennae with numbered antennomeres, scale bar = 0.5 mm. (b) Detail of last abdominal segments (lateral view), scale bar = 0.5 mm.