Balticopta gusakovi, Balashov & Perkovsky, 2020

Balticopta gusakovi View in CoL sp.n.

Fig. 1 View Fig .

Holotype: SIZK B-13 (original number in Gusakov’s collection CVGM No. 2MGP2011). The piece of amber is shaped similar to a triangular prism with side lengths of 10 mm, 9 mm and 7 mm, containing a single shell only.

Syninclusions: Diplopoda; Acari; two Diptera , Sciaridae and Cecidomyiidae ( Ledomyia sp. ) (CVGM, N 2 GP2011).

Description: Shell dextral, ovate-conic, with 4.5 moderately convex whorls. Coloration does not differ from surrounding amber. Shell surface almost smooth; very weak irregular striation visible on some whorls. Height of body whorl about half of shell’s height. Aperture free, complete, unusually large and extended to the wall of penultimate whorl forming sinulus in left upper corner (although partial deformation is possible), located relatively far forward from the body whorl; consequently, last whorl before aperturerelativelyelongatedformingsmallcurve (partly observable from palatal side, but unavailable for imaging because of the angle to the amber’s surface from this side). Margins of aperture with lip and reflected, including parietal margin. Inner aperture not easily observable due to dirt and air bubble in amber, inner columellar and basal walls are completely obscured. At least one angular lamellate tooth is present (partly visible among dirt on fig. 1, marked by arrow). It is simple, small, not bifurcate, located relatively deep in aperture, extend- ed further inside shell (its end inside shell is obscured). Tooth-like structure appears to be present on upper part of palatal wall, but we can’t rule out that this is dirt (visible on fig. 1, right from arrow). Other teeth may be present but unobservable. Umbilicus open, droplet-shaped, small, about 0.1 mm width.

Size: Width 1.3 mm, height 2.1 mm, body whorl’s and aperture’s height 1.1 mm, height of visible part of first whorl 0.2 mm, second whorl — 0.3 mm, third whorl — 0.5 mm.

Type locality: Yantarnyi (Kaliningrad region, Russia).

Age: Priabonian (late Eocene).

Etymology: The species is named after Viktor A. Gusakov (Zvyozdny gorodok, Moscow region, Russia), who kindly provided the amber piece containing the newly described species.