Haravex Posted November 6, 2017 Share Posted November 6, 2017 I have a question if Ichthyosaur is considered a reptile how come it gave birth to its young live? What separates it from mammals? Link to comment Share on other sites More sharing options...
flyg Posted November 7, 2017 Share Posted November 7, 2017 "Live birth" is not a reliable trait to differentiate among major vertebrate groups. There are quite a few species of extant snakes that give live birth. Similarly there are a number of fish that give live birth. Conversely there are a few mammals that lay eggs and a number of other non-placental mammals (marsupials) that are kind of intermediate in that they have live birth at an early stage of development and have special adaptations (eg. pouches) for young to develop. So, although most reptiles lay eggs, there is not a "problem" in terms of classification, with a reptile giving live birth. G 1 Link to comment Share on other sites More sharing options...
doushantuo Posted November 7, 2017 Share Posted November 7, 2017 I've posted at least ONCE time on viviparity in reptiles. Eggs and egg laying in non-eutherian mammals seem to be a special "aptation" Link to comment Share on other sites More sharing options...
Haravex Posted November 7, 2017 Author Share Posted November 7, 2017 Thank you for your insight I did not know this. Link to comment Share on other sites More sharing options...
JohnBrewer Posted November 7, 2017 Share Posted November 7, 2017 Extant (and no doubt extinct too) sea snakes give birth to live young. Monotreme mammals lay eggs but the mothers raise them with milk. John Map of UK fossil sites Link to comment Share on other sites More sharing options...
jpc Posted November 7, 2017 Share Posted November 7, 2017 mammals are classically defined as raising their young on their own mom-provided milk. The reptile definition is a bit more irregular. Link to comment Share on other sites More sharing options...
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