Search results
Results from the WOW.Com Content Network
Thecodontia (meaning 'socket-teeth'), now considered an obsolete taxonomic grouping, was formerly used to describe a diverse "order" of early archosaurian reptiles that first appeared in the latest Permian period and flourished until the end of the Triassic period. All of them were built somewhat like crocodiles but with shorter skulls, more ...
Thecodont dentition is a morphological arrangement in which the base of the tooth is completely enclosed in a deep socket of bone, as seen in crocodilians, dinosaurs and mammals, and opposed to acrodont and pleurodont dentition seen in squamate reptiles. [1] Notably, this appears to be the ancestral tooth condition in Amniota. [2]
This feature is responsible for the name "thecodont" (meaning "socket teeth"), [8] which early paleontologists applied to many Triassic archosaurs. [7] Additionally, non-muscular cheek and lip tissue appear in various forms throughout the clade, with all living archosaurs lacking non-muscular lips, unlike most non-avian saurischian dinosaurs. [ 9 ]
The thecodont condition was historically used to define a clade, the Thecodontia, which is now considered paraphyletic and thus obsolete. [7] angular The angular is a dermal bone of the lower jaw. In lateral view, it covers a larger area of the posteroventral region of the jaw, being located behind the dentary and below the surangular.
When the upper and lower dental formulae are the same, some texts write the formula without a fraction (in this case, 2.1.2.3), on the implicit assumption that the reader will realise it must apply to both upper and lower quadrants. This is seen, for example, throughout The Cambridge Dictionary of Human Biology and Evolution.
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
This did not change when Richard Owen coined the term Dinosauria in 1842, because Owen did not recognise Thecodontosaurus as a dinosaur; in 1865, he assigned it to the Thecodontia. It was not until 1870 that Thomas Huxley became the first person to understand that it was a dinosaur, though referring it incorrectly to the Scelidosauridae. [18]
Procompsognathus / ˌ p r oʊ k ɒ m p ˈ s ɒ ɡ n ə θ ə s / is an extinct genus of coelophysid theropod dinosaur that lived approximately 210 million years ago during the later part of the Triassic Period, in what is now Germany.