Imposex in Thais chocolata (Duclos 1832) (Gastropoda: Muricidae), Caldera Bay, Chile.

Yasna Marión Mattos Gajardo, María Soledad Romero



Imposex syndrome is the superimposition of a pseudopenis and vas deferens in the reproductive system of female gastropods. This anomalous virilization is attributed to a hormonal imbalance induced by tributyltin, present in antifouling paints. This study analyzes the severity, extent, degree and indices of imposex in 90 females of Thais chocolata from Caldera Bay, Atacama Region, Chile. Sex was determined by biopsy of the gonad of 180 specimens and imposex by the concurrence of ovarian, capsule gland, vas deferens and pseudopenis. Histopathological changes were analyzed in reproductive organs of females with imposex. The proportion of females affected was estimated using the formula described by Gibbs et al. (1987). The degree of progress of the syndrome was classified using five scales of imposex and VDSI, RPLI and RPSI indices were calculated from formulas of Gibbs. Macroscopic analysis revealed atrophy of the vagina and femenine glands. Some females lacked ingestive gland and seminal receptacle. Cytological disorders and overlapping of prostate tissue in the three female glands were found. Anatomical and histological alterations associated with imposex determine the absolute sterility of female. 100% of the females of T. chocolata from Caldera Bay suffer imposex. The syndrome reached maximum degrees in all scales except for that of Barreiro et al. (2001). In addition, indices of imposex reached high values. It is recommended the VDSI for T. chocolata, since provides a realistic measure of the virilization and reproductive potential of the females and would not be affected by the shape and size of the penis.

Mattos Gajardo Y, Romero M. Imposex in Thais chocolata (Duclos 1832) (Gastropoda: Muricidae), Caldera Bay, Chile.. Lat. Am. J. Aquat. Res.. 2017;44(4). Available from: doi:10.3856/vol44-issue4-fulltext-18 [Accessed 22 Jan. 2019].
Mattos Gajardo, Y., & Romero, M. (2017). Imposex in Thais chocolata (Duclos 1832) (Gastropoda: Muricidae), Caldera Bay, Chile.. Latin American Journal of Aquatic Research, 44(4). doi: