Zeynab Parvaresh; Mohsen Nokhbatolfoghahaei
Abstract
Bufotes surdus annulatus as a subspecies of B. sardus; endemic in the very limited area in Fars province with a specific reproductive strategy that has recently been reported to be threatened by extinction. Histological studies on gonads in adults as well as studies on gonadal differentiation aimed to ...
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Bufotes surdus annulatus as a subspecies of B. sardus; endemic in the very limited area in Fars province with a specific reproductive strategy that has recently been reported to be threatened by extinction. Histological studies on gonads in adults as well as studies on gonadal differentiation aimed to explore their reproductive strategy in more detail. In the reproductive season, fourteen males and females in adult stage were collected from Aliabad Niriz (Fars province). The gonads of the toads before and after mating (spawning and sperm releasing) were dissected and a histological study was carried out. To study gonadal differentiation, larvae at Gosner stage 40, 42, 43, 44 and 46 were selected and appropriate histological slides were prepared. Histology of the gonads in adults when they were in the amplexus situation and just before spawning and releasing sperm, showed a histologically similar image to Bufotes viridis that is a common toad that exist widely in the region. While the number of mature oocytes and spermatozoa were shown to be significantly reduced, some active oocytes as well as the bundles of spermatids were still observed in the ovary and testis respectively. The study on the gross anatomy of gonads at early stages of development showed there is no externally morphological difference between gonads in male and female. The semi differentiated pattern was recognized. The gonads in genetically male toads showed that they transformed into testes after degeneration of the oocytes.
