Notes on the systematics, morphology and biostratigraphy of fossil holoplanktonic Mollusca, 18. On the status of Cuvierina (Cuvierina) ludbrooki and C. (C.) jagti (Gastropoda, Euthecosomata)

Rediscovery of the holotype of the Pliocene Cuvierina ludbrooki (Caprotti, 1962), originally described as a scaphopod, has enabled the conclusion that it is specifically distinct from the Late Miocene C. jagti Janssen, 1995, in altogether lacking longitudinal micro-ornament. The relationships of C. astesana (Rang, 1829), C. ludbrooki and C. tubulata Collins, 1934 are studied by means of height/width-ratios. It is concluded that C. astesana and C. ludbrooki are valid species, while C. tubulata is considered to fall within the range of variation of C. astesana.