ONTOGENY OF THE PSEUDOHERMAPHRODITIC REPRODUCTIVE SYSTEM IN NASSARIUS VIBEX (GASTROPODA: BUCCINIDAE: NASSARIINAE)

Abstract

Pseudohermaphroditism or imposex is an abnormality of the gastropod reproductive system caused by the effects of an environmental pollutant, tributyltin, in which parts of the male reproductive tract develop in females. In this study, the post-larval development of the reproductive system in pseudohermaphroditic male and female Nassarius vibex was investigated relative to normal development to determine how and when the abnormalities associated with pseudohermaphroditism develop. Two populations of N. vibex were compared: one exhibiting normal development, and one in which the animals were effected by pseudohermaphroditism. In the affected N. vibex population, a penis and anterior spermiduct developed very early in ontogeny in both males and females. Normal reproductive system development was affected in some females, evidenced by fusion of the induced spermiduct and anterior oviduct, or by abnormal oviduct development. Several males displayed precocious maturation of the gonad in addition to early development of the anterior spermiduct and penis.