Observations on the Oman Shark, Iago omanensis (Triakidae), with emphasis on the morphological and cytological changes of the oviduct and yolk sac during gestation

Journal of Morphology
L Fishelson, A Baranes

Abstract

The shark Iago omanensis (Triakidae, Selachia) is encountered in large populations in the Gulf of Aqaba, Red Sea, at depths of 150-1,500 m. It is a placental viviparous species, reproductive all year round and giving birth to four (occasionally five) young of 170- to 180-mm total length (TL). Its distribution and morphometrics, as well as histological and cytological changes in the oviducts, were studied. The ratio of weight of the female genital organs to body weight changes from 0.7% in nongravid females to 19.8% in the final stages of pregnancy. The ripe, liberated eggs, which are 11-12 mm long and 5 mm wide, pass through the nidamental gland and settle in the uterus. The embryo attains 9- to 11-mm TL and settles on a protruding ridge of the submucosa, covered with a microvillar endometrium. At this site of attachment, a placenta is formed and the participating uterine endometrium and wall of the yolk sac undergo profound histocytological changes, forming two parts of this organ. Three forms of food provisioning occur in the growing embryos: (1) lecithotrophic, based on yolk transported from the egg to the embryonic gut via the umbilical cord; (2) mixed food provision, during which, in addition to nourishment provided via th...Continue Reading

References

Jun 1, 1985·Journal of Ultrastructure Research·W C HamlettJ S Hudson
Jun 1, 1985·Journal of Ultrastructure Research·W C HamlettJ S Hudson
Nov 1, 1966·Journal of Morphology·D A Schlernitzauer, P W Gilbert
Jan 1, 1984·Tissue & Cell·W C Hamlett, J P Wourms

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Citations

Apr 14, 2012·Journal of Fish Biology·J L Y SpaetM L Berumen
Dec 10, 1999·The Anatomical Record·L Fishelson, A Baranes
Jan 1, 2009·Journal of Morphology·Megan T StorrieWilliam C Hamlett
Oct 17, 2015·Journal of Morphology·Martina F MarongiuMaria C Follesa

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