Gonzalo A. Collado, Claudio L. Correa, Marco A. Méndez, and Donald I. Brown (2011) Recent phylogenetic analyses of Vetigastropoda using DNA sequences suggest that the subfamilies Prisogasterinae and Turbininae form a monophyletic group within the recently redefined family Turbinidae. To verify this systematic arrangement, we describe the spermatozoon ultrastructure of Prisogaster niger, a reproductive anatomical component that has been successfully used in phylogenetic investigations of vetigastropods, and compare the results with previously published information from other trochoidean taxa based on a phylogeny of the group. Prisogaster niger has a primitive spermatozoon, or aquaspermatozoon, typical of invertebrates with external fertilization. The sperm has a conical pointed acrosome which is > 50% of the head length, a barrel-shaped nucleus, a midpiece with 2 centrioles and 5 spherical mitochondria, and a simple flagellum with 9+2 axonemes. Compared to other trochoideans, the spermatozoon of P. niger is notably similar in structure to those of the Turbininae, with shared synapomorphies (e.g., an elongated conical pointed acrosome and a broad subacrosomal space) that suggest a close relationship between the Prisogasterinae and this subfamily, and that Prisogaster may have originated from an ancestral Turbininae.
Gastropoda, Turbinidae, Prisogasterinae, Sperm, Morphology.
