Description of the uterine modifications related with reproductive stages of the southern eagle ray Myliobatis goodei

COLONELLO, J.; CHRISTIANSEN, H.; COUSSEAU, M.; MACCHI, G. J.

ITALIAN JOURNAL OF ZOOLOGY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2013 vol. 80 p. 187 - 194

1125-0003

Uterine layers changes and their relationship with reproductive cycle was analyzed for the southern eagle ray Myliobatis goodei, based on histological and histometric studies. The specimens were collected from bottom-trawl surveys conducted in the coastal southwest Atlantic ecosystem between latitude 34° and 42°S. Oviducts samples were removed and fixed in 10% buffered formalin until processing for histological analysis. Both oviducts are developed in mature females, but only the left is functional. After ovulation, the size of the right posterior oviduct decreases and the left develops into a complex uterus that occupies almost the entire coelomic. This uterus undergoes successive morphological and functional changes related to reproductive stages. Mucosa was characterized by temporal villous extensions or trophonemata with high variability depending on reproductive events. Invaginations or crypts associated with presumably lipid secretory (histotrophe) were observed between each trophonematum bases. Muscular layer develops into a complex muscular-vascular-conjunctive structure. The nutrition of early gestation embryos is lecithotrophic and later they receive nutrients from the yolk sac and histotrophe. After yolk depletion, embryos become entirely dependent on histotrophe. Uterolactation, presumptive water imbibition of muscular layer and uterine hypertrophy observed in this study, reinforce the similarities between Myliobatiformes and mammals.