Robulus cultrata de Montfort, 1808, p. 214, fig. 54e.
Lenticulina cultrata Kohl, 1985, p. 47, pl. 10, fig. 6–7; Weidich, 1990, p. 123.
Description: The wall is calcareous, smooth and finely perforate. The test is planispiral, involute and biconvex, with a peripheral keel. The chambers gradually increase in size toward the terminal aperture. The sutures are flush and slightly curved. The aperture is radiate and terminal.
Remarks: Specimens are relatively large, with a diameter of up to 1 mm. The relative abundance is generally low, forming minor components (<5%) in some of the core samples.
Lenticulina cultrata is similar to other species in this genus, but can be distinguished by its rounded shape and concave profile, that is supported by its central pillar. The terminal apertural face is also straight, extending from the aperture to the central boss.
Life strategy: Species of the genus Lenticulina are generally epifaunal (Corliss and Chen, 1988) under oxic (Pezelj et al., 2013 and references therein) to suboxic conditions (Kaiho, 1994).
Global stratigraphic range: McMillan (2003) identified L. cultrata in Cretaceous deposits, extending the stratigraphic range for this species to that period.
Regional occurrence: This species has been reported in early Cretaceous-aged deposits of the Eastern Cape, South Africa (McMillan, 2003). This study documents the species in middle Miocene sediments on the Namibian outer continental shelf, south of the Kunene River mouth (this study).