toothcomb

The toothcomb is a dental structure consisting of forward-projecting, closely spaced incisors, and sometimes canines, on the lower jaw of certain mammals, most notably strepsirrhine primates. In these animals, the lower incisors and often the canines are procumbent and form a comb-like array that extends outward from the tooth row. The upper teeth do not participate in the arrangement.

The toothcomb is primarily used for grooming. By brushing fur, the comb helps remove dirt, debris, and parasites, contributing to social bonding in group-living species. In some species, the toothcomb also participates in foraging; it can be used to scrape gum or sap from tree bark, or to help in processing certain foods.

Distribution and evolution: A toothcomb is characteristic of many strepsirrhine primates, including lemurs, lorises, and galagos. It is viewed as a derived dental specialization that arose from the forward projection of the anterior dentition. In haplorrhine primates (monkeys, apes, and humans) and in most other mammals, a true toothcomb is absent or greatly reduced.

Variations and terminology: The structure may vary in the degree of projection among species, and some lineages may rely more on one or the other tooth for grooming. The term dental comb is sometimes used specifically to refer to the combined lower incisors and canines forming the grooming structure.