Cochlis sp.

Cochlis sp.

Figs 21B View FIGURE 21 1 –B View FIGURE 1 3 View FIGURE 3

Illustrated material. PIN 5904/125, SL: 7.9 mm, MD: 7.8 mm, ravine Kiyandy, Kazakhstan, Middle Miocene, late Konkian, Figs 21B View FIGURE 21 1 –B View FIGURE 1 3 View FIGURE 3 .

Description. Small, globose shell of about four whorls; nearly as wide as high (SL/MD = ~1). Spire low conical, with moderately convex whorls; apical angle 125°. Protoconch unknown. Suture linear, narrow, weakly incised. Last teleoconch whorl with narrow, flattened subsutural shelf, delimited by faint shoulder angulation. Last whorl rapidly expanding, attaining 93% of total height. Periphery placed mid-whorl, regularly convex. Growth lines poorly preserving, strongly prosocline in apical view close to adapical suture. Aperture moderately wide, D-shaped. Aperture 81% of total height. Umbilicus moderately wide (~19%), deep, with prominent growth lines. Parietal callus thin with insignificant adapical swelling. Prominent, broad, cord-like funicle, situated just in center of umbilicus, terminating in small, semicircular umbilical callus. Adapical and abapical sulci equal in width, but adapical sulcus deeper, limited by steep adapical wall of funicle and parietal callus.

Discussion. This form is known only from a single small shell that might be subadult. It differs from other Cochlis species in its broad funicle located in central position in the umbilicus. This feature, however, may be an ontogenetical feature of a subadult specimen.

Paleoenvironment. Shallow marine, inner neritic.

Central Paratethys. Konkian (Middle Miocene): Transcaspian Region: ravine Kiyandy (Mangystau Region, Kazakhstan) ( hoc opus).

Genus Naticarius Duméril, 1805 View in CoL

Type species. Nerita canrena Linnaeus, 1758 ; subsequent monotypy ( Froriep 1806: 165). Present-day, western Atlantic.

Discussion. The species of the genus Naticarius have the teleoconch similar to that of Cochlis , but their opercula have the outer surface with many ribs instead of two to three. Therefore, we cannot ascribe species to Naticarius without their protoconch, but see below.