Cantrainea sp.

Kiel, Steffen, Hybertsen, Frida, Hyžný, Matúš & Klompmaker, Adiël A., 2020, Mollusks and a crustacean from early Oligocene methane-seep deposits in the Talara Basin, northern Peru, Acta Palaeontologica Polonica 65 (1), pp. 109-138 : 123

Cantrainea sp.

Fig. 12A, B .

Material.— One specimen (NRM Mo187040) from Cerro La Salina block 1; one (NRM Mo187041) from Cerro La Salina block 9; a single poorly preserved specimen possibly also belonging to Cantrainea sp. is present on the same sample as Provanna pelada (NRM Mo187054) from Cerros El Pelado block 2. All upper Oligocene, Talara Basin, Peru.

Description.—Small, trochiform shell with angular whorl profile and moderately wide umbilicus; subsutural ramp slightly convex and only slightly sloping, smooth except for strongly prosocline growth lines, margin to whorl’s flank marked by fine groove and smooth keel; flank vertical, smooth except for fine axial growth lines; basal margin also marked by smooth keel; base smooth with inclination of about 45°; umbilicus occupying about 20 of base’s width.

Remarks.—Most similar is Cantrainea macleani Warén and Bouchet, 1993 from Recent seeps in the Gulf of Mexico, which differs by its more conical shell, resulting from a steeper subsutural ramp that is concave rather than convex as in the specimen reported here. Indeed, most fossil and Recent species of Cantrainea have a steeper subsutural ramp than the Peruvian specimens illustrated here ( Marshall 1979; Vilvens 2001; Okutani 2001; Kaim et al. 2009).

Figures

Fig. 12. Vetigastropoda from early Oligocene seep deposits at Cerro La Salina (block 1, A, D; block 2, C; block 9, B) Talara Basin, northern Peru. A, B. The colloniid Cantrainea sp. A. NRM Mo187040, specimen with base embedded in rock matrix in lateral (A1), oblique (A2) and apical (A3) views. B. NRM Mo187041, specimen with exposed base in lateral (B1) and basal (B2) views. C, D. The trochoid incertae sedis. C. NRM Mo187042. D. NRM Mo187043.