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Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch.
Among mammals, the monotremes are oviparous. Ovo-viviparity: or oviparity with retention of zygotes in either the female's or in the male's body, but there are no trophic interactions between zygote and parents. [1] This mode is found in the slowworm, Anguis fragilis. In the sea horse, zygotes are retained in the male's ventral "marsupium".
The traditional modes of reproduction include oviparity, taken to be the ancestral condition, traditionally where either unfertilised oocytes or fertilised eggs are spawned, and viviparity traditionally including any mechanism where young are born live, or where the development of the young is supported by either parent in or on any part of their body.
An aphid giving viviparous birth, an unusual mode of reproduction among insects. In animals, viviparity is development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juvenile that is at least metabolically independent.
Drawing of the animal and shell of Viviparus viviparus; a) head b) tentacles c) eyes d) foot e) operculum. The height of the shell is 25–35 mm. The width of the shell is 20–26 mm. Males are 2 mm smaller than females of the same age. The shell colour is dark greenish brown or greyish yellow, with three reddish brown spiral bands.
All skates and some rays are oviparous (egg laying) while other rays are ovoviviparous, meaning that they give birth to young which develop in a womb but without involvement of a placenta. [ 7 ] The eggs of oviparous skates are laid in leathery egg cases that are commonly known as mermaid's purses and which often wash up empty on beaches in ...
Ovoviviparous and viviparous fish compared [ edit ] Most of the Poeciliidae are ovoviviparous , that is, while the eggs are retained inside the body of the female for protection, the eggs are essentially independent of the mother and she does not provide them with any nutrients.
Zenarchopteridae, the viviparous halfbeaks, is a family of ray-finned fishes in the order Beloniformes. The Zenarchopteridae exhibit strong sexual dimorphism , practicing internal fertilisation , and in some cases ovoviviparous or viviparous (the family also includes oviparous species).