The toothcomb is a specialized dental arrangement in various mammals, where front teeth are configured to resemble a comb. This unique structure primarily facilitates grooming, allowing animals to effectively comb through their fur. The toothcomb highlights an interesting example of evolutionary adaptation.
Anatomy of the Toothcomb
The toothcomb consists of elongated, closely spaced lower incisors and canines that project forward. In most lemuriforms, this structure comprises six teeth: four incisors and two canines, all tilting forward. The crowns of these incisors and canines are elongated, compressed side-to-side, and angled to match this forward tilt. The lower canine teeth within the toothcomb are similar in shape to the incisors but are more robust and curve slightly upward and inward. This creates fine spaces between the teeth, allowing them to function like the tines of a comb.
Animals Possessing a Toothcomb
The toothcomb is most widely recognized in strepsirrhine primates, a suborder that includes lemurs, lorises, and galagos. Beyond strepsirrhines, toothcombs can also be found in other mammals such as treeshrews, colugos (also known as flying lemurs), hyraxes, and some African antelopes. While the toothcomb serves a similar purpose across these diverse groups, its specific dental composition and structure can vary due to independent evolutionary development. For instance, the toothcomb of colugos and hyraxes differs from that of lemuriforms, as their individual incisors are serrated, providing multiple tines per tooth rather than relying on spaces between distinct teeth.
Diverse Functions of the Toothcomb
The primary function of the toothcomb is grooming. Animals use this comb-like structure to comb their fur, removing parasites, dirt, and other debris. This grooming behavior maintains hygiene and overall health, and also plays a role in social bonding among group-living species. Fine grooves or striations are often observed on the sides of the teeth, providing evidence of their regular use. To keep the toothcomb clean, many lemuriforms possess a specialized “under-tongue” called a sublingua, which acts like a small brush to remove trapped hair and debris.
Beyond grooming, the toothcomb also serves various secondary functions in certain species. For example, some lemuriforms utilize their toothcomb for food procurement. This can involve scraping tree bark for gums or sap, processing fruits, or prying open crevices to extract insects. Fork-marked lemurs and indriids, for instance, possess more robust toothcombs, better suited for demanding feeding activities like bark gouging. These diverse applications highlight the adaptability of this specialized dental structure to different dietary and behavioral needs.