Toothcomb
The toothcomb occurs in lemuriform primates, treeshrews, colugos, hyraxes, and some African antelopes. The teeth are arranged in a manner that facilitates grooming, similar to a hair comb. In some lemurs, such as the aye-aye, the toothcombs have been lost completely and replaced with other specialized dentition.
About Toothcomb in brief
The toothcomb occurs in lemuriform primates, treeshrews, colugos, hyraxes, and some African antelopes. The structures evolved independently in different types of mammals through convergent evolution. In most mammals the comb is formed by a group of teeth with fine spaces between them. The toothcomb is usually used for grooming. While licking the fur clean, the animal will run the toothcomb through the fur to comb it. Fine grooves or striations are usually cut into the teeth during grooming by the hair and may be seen on the sides of the teeth when viewed through a scanning electron microscope. The French anatomist Marie Ducrot de Blainville identified the two lateral toothcomb teeth of theLemuriforms as the upper and lower incisors. The upper incisor and lower canine are often reduced or lost completely, often with no contact with one another. The lower canine is more robust and inwardly curved, and the crowns of both the inc isors and canisors are elongated and compressed. The crowns are also angled in the direction of the forward tilt of the incisory teeth, and are also elongated along the side-to-side ridge. As a result of this dental reconfiguration, the lower canine teeth tapering off from the midline of the upper inc isor is called the lateral canisiform, the mid-line isor, the lateral incisiform and the canisial are all called lateral caniniform. The teeth are arranged in a manner that facilitates grooming, similar to a hair comb.
In some lemurs, such as the aye-aye, the toothcombs have been lost completely and replaced with other specialized dentition. The fossil record suggests that they evolved from an older lineage that migrated to Africa during the Paleocene and might have evolved from early cercamoniines from Asia. Fossil primates such as Djebelemur, ‘Anchomomys’ milleri, and Plesiopithecus may have been their closest relatives. The lack of a distinct toothcomb in the fossil record before to 40 mya has created a conflict with molecular clock studies that suggest an older divergence between lemururs and lorisoids, and the existence of a ghost lineage of lemuroid primates in Africa. The homologous structure is a diagnostic character that helps define this clade of primates. An analogous trait is found in the bald uakari, a type of New World monkey. Toothcombs can also be found in colugo and treeshreys, both close relatives of primates; however, the structures are different and these are considered to examples of convergent evolution and these are considered to be examples of convergent history. The structure has been used by scientists in the interpretation of the evolution of leMurs and their kin. They are thought to have evolved from early adapiform primates around the Eocene or earlier.
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This page is based on the article Toothcomb published in Wikipedia (as of Nov. 30, 2020) and was automatically summarized using artificial intelligence.
