Search results
Results from the WOW.Com Content Network
Model of a dinosaur egg. Dinosaur reproduction shows correlation with archosaur physiology, with newborns hatching from eggs that were laid in nests. [1] [2] Dinosaurs did not nurture their offspring as mammals typically do, and because dinosaurs did not nurse, it is likely that most dinosaurs were capable of surviving on their own after hatching. [3]
No dinosaur egg has been found that is larger than a basketball and embryos of large dinosaurs have been found in relatively small eggs, e.g. Maiasaura. [53] Like mammals, dinosaurs stopped growing when they reached the typical adult size of their species, while mature reptiles continued to grow slowly if they had enough food.
Dinosaurs are unique in showing a perforate or open acetabulum, where the full extent of the socket is a hole without infilling bone. [1] acromion The acromion is a bony ridge on the lower part of the scapula that functions in providing an attachment for the clavicle.
Most elongated eggs were laid by theropods and have an avian-like eggshell, whereas the spherical eggs typically represent non-theropod dinosaurs. [13] Diagram of a two-layered eggshell. Fossil dinosaur eggshells, like modern bird and reptile eggshells, are made up of calcium carbonate crystal units.
Dinosaur classification began in 1842 when Sir Richard Owen placed Iguanodon, Megalosaurus, and Hylaeosaurus in "a distinct tribe or suborder of Saurian Reptiles, for which I would propose the name of Dinosauria." [1] In 1887 and 1888 Harry Seeley divided dinosaurs into the two orders Saurischia and Ornithischia, based on their hip structure. [2]
A microbiologist named João Pedro de Magalhães has proposed the idea that the reign of dinosaurs forced mammals to speed up their reproductive cycle, eliminating key longevity genes.
Brachiosaurus (/ ˌ b r æ k i ə ˈ s ɔː r ə s /) is a genus of sauropod dinosaur that lived in North America during the Late Jurassic, about 154 to 150 million years ago. [1] It was first described by American paleontologist Elmer S. Riggs in 1903 from fossils found in the Colorado River valley in western Colorado, United States.
The presence of two shelled eggs within the birth canal shows that oviraptorosaurs were intermediate between the reproductive biology of crocodilians and modern birds. Like crocodilians, they had two oviducts. However, crocodilians produce multiple shelled eggs per oviduct at a time, whereas oviraptorosaurs, like birds, produced only one egg ...