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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]
In contrast, Archosauromorphs possess a parasagittal gait, a reduction in their dermal girdle, a reduction and/or loss of the sternum, and a more thecodont dentition. Living lepidosauromorphs have retained an ectothermic (" cold blooded ") metabolism, unlike the ancestral condition in archosauromorphs.
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.
For example, members of the Synapsida generally possess incisors, canines ("dogteeth"), premolars, and molars. The presence of heterodont dentition is evidence of some degree of feeding and or hunting specialization in a species .
Any chemical substance with biological activity may be considered a drug. This list categorises drugs alphabetically and also by other categorisations. This multi-page article lists pharmaceutical drugs alphabetically by name. Many drugs have more than one name and, therefore, the same drug may be listed more than once.
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 . [ 19 ]
Pharmacognosy is the study of crude drugs obtained from medicinal plants, animals, fungi, and other natural sources. [1] The American Society of Pharmacognosy defines pharmacognosy as "the study of the physical, chemical, biochemical , and biological properties of drugs, drug substances, or potential drugs or drug substances of natural origin ...