INTEGBI N33 Lecture Notes - Lecture 19: Maiasaura, Dinosaur Egg, Eggshell
31 Mar 2018
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Document Summary
Fish and amphibians; females deposit eggs and males deposit sperm over eggs. Needed by amniotes because eggs have shell and is laid on dry land so can"t be fertilized externally. Male structure for depositing sperm into female. Hole/duct for excreting urine and excrement used by vertebrates. Male structure that deposits sperm into females. Area in arms and legs for depositing calcium. Egg shells need calcium so when pregnant, female dinosaurs deposit lots of calcium in medullary bone. Analysis of calcium content in fossil medullary bone can indicate that dinosaur was pregnant. Cloacal penis because it"s what other archosaurs have. Musculature for cloaca attached to first chevron and in male dinosaurs, first chevrons are enlarged, indicating attachment of cloacal penis. Cloaca can be turned inside out and filled with blood to become intro. Many examples of dinosaurs caring for eggs. Oviraptor fossils often found brooding over nests and found nests with baby dromaeosaur, indicating mother brought food for young.
