This shows that viviparity and internal fertilisation was common amongst these primitive jawed vertebrates, which are outside the crown group Gnathostoma.
12.
This is known as " yolk-sac viviparity " and is regarded as a type of lecithotrophy ( no maternal provisioning ).
13.
Viviparity in " Incisoscutum " and the ptyctodontids show that these placoderms were the first K-strategists in relation to breeding.
14.
Several groups of Mesozoic marine reptiles also exhibited viviparity, such as mosasaurs, ichthyosaurs, and Sauropterygia, a group that include pachypleurosaurs and Plesiosauria.
15.
"Aplacentral viviparity " occurs when the female retains the embryos during the entire time of development but without any transfer of nutrients to the young.
16.
This method of reproduction is similar to viviparity, but the embryos have no placental connection with the mother and receive their nourishment from a yolk sac.
17.
In horned lizards ( genus " Phrynosoma " ), viviparity ( live birth ) has evolved multiple times, based on ancestral reconstruction methods.
18.
Did viviparity give air-breathers the edge to become truly marine and to reach large sizes, or did large sizes and a completely marine lifestyle force viviparity?
19.
Did viviparity give air-breathers the edge to become truly marine and to reach large sizes, or did large sizes and a completely marine lifestyle force viviparity?
20.
In many ways, depending on the ecology and life strategy of the species, viviparity may be more strenuous and more physically and energetically taxing on the mother than oviparity.
