Description of the reproductive tract and gonad histology of a second form of hermaphroditism in the Port Jackson sharkHeterodontus portusjacksoni

Abstract

Sampling of commercial fisheries bycatch in south-western Australia has yielded a second and different form of hermaphrodite of the Port Jackson sharkHeterodontus portusjacksoni. Its total length (706 mm) and weight (2740 g) fall within the range of those of mature males, but below those of mature females. The left clasper was similar to that of normal mature males, whereas the right clasper was far smaller, had a poorly-developed rhipidion groove and lacked a spur. The body cavity possessed a testis on the left, an ovotestis on the right, and contained sperm ducts, oviducal glands and uteri on both sides. As with normal mature males, the testis and the testicular component of the ovotestis contained germ cells in various stages of spermatogenesis, including late stage spermatids. The ovarian component of the ovotestis contained 14 follicles that were larger (5–9 mm diameter) than those of normal females of similar size, which were immature, but far smaller than those of normal mature females. Six of those follicles were atretic. The widths of the left and right oviducal glands and uteri were far greater than those of normal females of similar size, but similar to those of normal mature females. Thus, although gonadal maturation had progressed further in the testis and the testicular component of the ovotestis than in the ovarian component of the ovotestis, the oviducal glands and the uteri of the hermaphrodite were of similar size to those of normal mature females and were far better developed than those of normal females of similar length, which are immature.