02432nas a2200241   4500008004100000022001400041245010400055210006900159260001600228300001100244490000900255520163800264653001201902653002501914653001401939653001101953653001801964653001201982653001001994100002202004700002602026856013802052       2011                        eng d  a1552-501500aEvolution of developmental pattern for vertebrate dentitions: an oro-pharyngeal specific mechanism.0 aEvolution of developmental pattern for vertebrate dentitions an   c2011 Mar 15  a99-1120 v316B3 a<p>Classically the oral dentition with teeth regulated into a successional iterative order was thought to have evolved from the superficial skin denticles migrating into the mouth at the stage when jaws evolved. The canonical view is that the initiation of a pattern order for teeth at the mouth margin required development of a sub-epithelial, permanent dental lamina. This provided regulated tooth production in advance of functional need, as exemplified by the Chondrichthyes. It had been assumed that teeth in the Osteichthyes form in this way as in tetrapods. However, this has been shown not to be true for many osteichthyan fish where a dental lamina of this kind does not form, but teeth are regularly patterned and replaced. We question the evolutionary origin of pattern information for the dentition driven by new morphological data on spatial initiation of skin denticles in the catshark. We review recent gene expression data for spatio-temporal order of tooth initiation for Scyliorhinus canicula, selected teleosts in both oral and pharyngeal dentitions, and Neoceratodus forsteri. Although denticles in the chondrichthyan skin appear not to follow a strict pattern order in space and time, tooth replacement in a functional system occurs with precise timing and spatial order. We suggest that the patterning mechanism observed for the oral and pharyngeal dentition is unique to the vertebrate oro-pharynx and independent of the skin system. Therefore, co-option of a successional iterative pattern occurred in evolution not from the skin but from mechanisms existing in the oro-pharynx of now extinct agnathans.</p>
10aAnimals10aBiological Evolution10aDentition10aFishes10aOdontogenesis10aPharynx10aTooth1 aFraser, Gareth, J1 aSmith, Moya, Meredith  uhttps://chondrichthyes.myspecies.info/content/evolution-developmental-pattern-vertebrate-dentitions-oro-pharyngeal-specific-mechanism