See text Bostrycapulus, commonly known as the spiny slipper snails, is a genus of sea snails in the family Calyptraeidae.

[3] Before 2005, the snails in this genus were all thought to belong to one species, which was known as Crepidula aculeata, the spiny slipper snail.

[1] However, morphological and DNA sequence data show that the spiny slipper snails are a monophyletic group that is more closely related to Crepipatella than it is to Crepidula.

[1] However, molecular phylogenetic and anatomical work have shown them to be a separate monophyletic grouping or clade, which has elevated them to the genus status.

[1] DNA sequence data has also been used in combination with embryological observations to distinguish 8 species.