Spermatogenesis and sperm structure in the black-striped pipefishSyngnathus abaster(Teleostei, Syngnathidae) = Spermatogenesi e struttura degli spermatozoi inSyngnathus abaster(Teleostei, Synghathidae)

The gonads of adult males of the black-striped pipejishSyngnathus abasterwere observed during the reproductive season to describe mature sperm both quantitativel/y and qualitatively. The results show that: a) the sperms number is always very low and, does not vary significantly during the reproductive season; b) all mature sperms observed may be assigned to the introsperm-like type. These data suggest that the unique and functional sperm of Syngnathids pertain to the introsperm type typical of internally fertilizing teleostean bony fishes.