Adult and juvenile specimens of Dasyatis sabina were collected throughout 1976 and 1977. Embryos were collected from gestating females in both years. Representative specimens were examined for gross and histological anatomy and seasonal change. Females became sexually mature between 225 and 240 mm DW; males, between 205 and 215 mm DW. Anatomically, the reproductive systems of D. sabina appeared to be typical in most respects to other myliobatoids. Seasonally, males underwent a distinct annual cycle. Spermatogenesis followed typical elasmobranch patterns and served as a marker for the cycle which consisted of five phases, latent (May to August), early spermatogenesis (August to November), mid-spermatogenesis (September to February), late spermatogenesis (February to April), and pre-latent (April to May). Males contained ripe sperm in their seminal vesicles from September to May. Females also exhibited a yearly cycle. Though oocytes continually developed over the entire year, most underwent atresia. However, each year one group began to enlarge in the summer and continued to develop to maturation in April. Mating occurred at least twice (Fall and Spring) and sperm cells were observed in association with the uterine lining in a manner that suggested sperm storage from October to April. Ovulation and fertilization occurred in April and gestation continued to July or August. During the later stages of fetal development the uterine lining of the mother underwent dramatic changes associated with the secretion of an histotroph. Birth occurred when fetuses were between 100 and 135 mm DW. Brood size ranged from one to four but most females contained two fetuses. / Source: Dissertation Abstracts International, Volume: 43-03, Section: B, page: 0650. / Thesis (Ph.D.)--The Florida State University, 1982.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74807 |
| Contributors | LEWIS, THOMAS C., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 218 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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