Cerithidium iljinae, Harzhauser & Guzhov & Landau, 2025

Cerithidium iljinae sp. nov.

Figs 26A–B View FIGURE 26

Type material. Holotype, PIN 5904 View Materials /34, SL: 3.1 mm, MD: 1.16 mm, Shirvanskaya ( Russia), Tarkhanian, Middle

Miocene, Figs 26A View FIGURE 26 1 –A View FIGURE 1 2 View FIGURE 2 . Paratype, PIN 5904 View Materials /35, Shirvanskaya ( Russia), Tarkhanian , Middle Miocene , Fig. 26B View FIGURE 26 . Additional material. 9 spec., Shirvanskaya ( Russia), Tarkhanian , Middle Miocene. Type locality. Shirvanskaya ( Russia). Type stratum. Coquina in clay. Age. Middle Miocene, Tarkhanian (Langhian) .

Etymology. In honor of Lubov’ Iljina, explorer of gastropods of the Eastern Paratethys and the Pleistocene Black Sea.

Diagnosis. Small, slender shell, protoconch of 2.5 convex whorls terminating in deep sinusigera, six teleoconch whorls, initially angled mid-whorl, last whorl convex, sculptured by two primary spirals and 2–3 secondaries over subsutural ramp, overriding broad low ribs.

Description. Small, slender shell of six convex teleoconch whorls, attaining 3–3.5 mm in height; apical angle 25°. Protoconch of two whorls, with deep sinusigera (dp = ~ 230 μm). First teleoconch whorl with two prominent spiral cords. Suprasutural cord becomes visible on second teleoconch whorl. Subsutural ramp widening during ontogeny, with up to two secondary cords and one to two tertiary threads (up to four spiral elements). Additional spiral thread may appear between primary cords. Later whorls with broad subsutural ramp, subcylindrical periphery, tapering below abapical primary spiral cord. Suture moderately incised, linear. Primary cords hardly swollen over ribs, adapical one coinciding with mid-whorl angulation. Spiral cords overrunning low and wide axial ribs forming faint elongate swellings at intersections, most prominent on adapical primary cord. Ribs weakening further abapically. Last whorl convex, attaining about 42% of total height. Base with two prominent peribasal spiral cords and four weaker cords on base and fasciole. Aperture ovate, only partly preserved. Columellar callus forming thin, narrow rim. Anal and siphonal canal not preserved.

Discussion. Cerithidium iljinae sp. nov. differs from Cerithidium plebeium Lozouet, 1998 ( France, Late Oligocene—Early Miocene, Aquitanian) in the less prominent axial sculpture and the less numerous spiral cords. Cerithidium channakodiense Harzhauser, 2014 ( India, Early Miocene, Burdigalian) has a taller protoconch (three whorls), weaker secondary spiral cords, more prominent axial ribs and varices on late whorls. Cerithidium indicum (Harzhauser, 2014) from the same locality in India has only two primary cords, additional spiral threads and more prominent axial ribs. Cerithidium iljinae differs from the type species, C. submammillatum Rayneval & Ponzi, 1854 , in its weaker axial sculpture, narrower secondary spiral cords and the absence of varices.

Paleoenvironment. Unknown.

Distribution. Tarkhanian (Langhian) of the Eastern Paratethys Sea.

Eastern Paratethys Sea. Tarkhanian (Middle Miocene): Ciscaucasia : Shirvanskaya ( Russia).