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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]
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 ...
There is still some debate about the age of Magdalenian Girl. For years, the individual was thought to be a young girl, because her wisdom teeth had not yet advanced, but new analysis indicates that her wisdom teeth were impacted, and that she was actually 25 to 35 years old when she died. [6] This is the oldest recorded case of impacted wisdom ...
The teeth in the upper and lower jaws in mammals have evolved a close-fitting relationship such that they operate together as a unit. "They 'occlude', that is, the chewing surfaces of the teeth are so constructed that the upper and lower teeth are able to fit precisely together, cutting, crushing, grinding or tearing the food caught between." [5]
The lingual (tongue) side of pleurodont teeth are not attached to bone, and instead are typically held in place by connective ligaments. This contrasts with thecodont implantation, in which the teeth are set in sockets and surrounded by bone on all sides. [2] [3] [4]
C. petrinus has a particular form of thecodont dentition, its teeth appearing to be fused at the bottom of the alveoli. [70] C. duelferi has a subthecodont type of dentition, meaning that its teeth are implanted in shallow sockets. [10] C. youngorum has a thick base of the bone attaching to the teeth, [11] a trait not seen in other ichthyosaurs ...
New, permanent teeth grow in the jaws, usually under or just behind the old tooth, from stem cells in the dental lamina. [5] Young animals typically have a full set of teeth when they hatch; there is no tooth change in the egg. Within days, tooth replacement begins, usually in the back of the jaw continuing forward like a wave.
Conodont elements consist of mineralised teeth-like structures of varying morphology and complexity. The evolution of mineralized tissues has been puzzling for more than a century. It has been hypothesized that the first mechanism of chordate tissue mineralization began either in the oral skeleton of conodonts or the dermal skeleton of early ...