Spermatozoal ultrastructure in the Hippoidea (Anomura, Decapoda)

Three species of anomuran mole and sand crabs (Albunea sp., Emerita talpoid a and Hippo pacifica) in the superfamily Hippoidea are investigated for spe rmatozoal ultrastructure. Each species has a different spermatozoal morphol ogy but shares, with the others, three apomorphies - a thickened, multi-lay ered operculum, a perforatorial septum, and a central acrosome zone. The sp ermatozoa of A. sp. (family Albuneidae) possess numerous perforatorial spik es which emanate from the anterior of the perforatorium and contain electro n-dense tubes of longitudinally aligned granules. These densely filled perf oratorial spikes are not found in the other species, E. talpoida and H. pac ifica, from the family Hippidae. The spermatozoa of E. talpoida are distinc t in having an elongate acrosome vesicle, a four chambered perforatorium an d a conical operculum. All three taxa share significant spermatozoal charac ters which unite them, but their relationships to other investigated anomur an crabs is still unknown.