Palatal tooth

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A palatal tooth can be part of the teeth of fish , amphibians , snakes and lizards . Usually these are very small teeth that sit in the roof of the mouth. They are used to hold on to the prey. Especially when there are no other teeth in the jawbone , the palatal teeth take over this task. In the animal groups mentioned, they grow back again and again.

The presence, number and position of the palatal teeth is of great importance for the classification of species and genera. These tooth formations are mostly still preserved in fossil form , for example in finds from ancestors of reptiles and amphibians such as the Trematosauria . Sclerocephalus , an amphibian that lived in freshwater 290 million years ago, had three pairs of tusk-like teeth that were used to hold large fish in place. In many representatives of the Capitosauria from the Triassic period around 220 million years ago, the palatal teeth were roughly the size of the teeth on the jawbone.

Reptiles

Underside of the upper jaw of Placodus gigas , in the middle the six broad palatal teeth

Some of the reptiles living today also have teeth on the wing legs, for example most representatives of the real lizards , skinks or agamas .

The teeth of Placodus gigas , a diapsid reptile from the lower Triassic, comprised a total of six palatal teeth in addition to the teeth on the upper and lower jaw. The palatal teeth were flat and very wide. They had a thick layer of enamel on them .

Amphibians

In amphibians, teeth can also sit on the ploughshare ( vomer ). Often these vomer teeth are also referred to as palatal teeth.

In the case of the transverse newts , the arrangement of the palatal teeth in transverse rows gives the family its name.

fishes

In many carp fish that have toothless jaws, a chewing plate with keratinized surface is located at the base of the skull (more precisely on the pharyngeal process) and serves as a counterpart to the lower pharyngeal teeth . Similar friction and chewing plates on the roof of the mouth can be found in many other fish, e.g. B. with the striped lyrefish , the sand smelt , with the toothfish genus Fundulus , with the common garfish , with the jackfish , with half-beak , with the filefish , the sunfish , ballfish and porcupine fish , as well as with parrotfish . In all cases, these palatal plates work against similar structures at the base of the gill arches and enable the food to be crushed.

Individual evidence

  1. ^ The dinosaurs from Odernheim am Glan . World of Knowledge, March 7, 2007; Retrieved February 17, 2014 ( JSTOR 1447343 ).
  2. Hermann Burmeister: The labyrinthodonts from the colorful sandstone of Bernburg. 1st division: Trematosaurus. Berlin 1849, p. 33
  3. Kurt Fiedler: Textbook of Special Zoology . Volume II, Part 2: Fish . Gustav Fischer Verlag, Jena 1991, ISBN 3-334-00339-6 , p. 57