This article is about the tooth structure, for the comb see nit comb.

A toothcomb (tooth comb, dental comb) is an anatomical

Anatomy

Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...

 structure found in strepsirrhine

Strepsirrhini

The clade Strepsirrhini is one of the two suborders of primates. Madagascar's only non-human primates are strepsirrhines, and others can be found in southeast Asia and Africa...

 primate

Primate

A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...

s, which includes lemur

Lemur

Lemurs are a clade of strepsirrhine primates endemic to the island of Madagascar. They are named after the lemures of Roman mythology due to the ghostly vocalizations, reflective eyes, and the nocturnal habits of some species...

s, loris

Loris

Loris is the common name for the strepsirrhine primates of the subfamily Lorisinae in family Lorisidae. Loris is one genus in this subfamily and includes the slender lorises, while Nycticebus is the genus for the slow lorises....

es and galago

Galago

Galagos , also known as bushbabies, bush babies or nagapies , are small, nocturnal primates native to continental Africa, and make up the family Galagidae...

s. A toothcomb consists of long, flat forward-angled teeth, and includes the lower

Mandible

The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...

 incisor

Incisor

Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...

s and the canine teeth

Canine tooth

In mammalian oral anatomy, the canine teeth, also called cuspids, dogteeth, fangs, or eye teeth, are relatively long, pointed teeth...

. In indriid

Indriidae

The Indriidae are a family of strepsirrhine primates. They are medium to large sized lemurs with only four teeth in the toothcomb instead of the usual six...

s, archaeolemurid

Archaeolemurinae

The Monkey lemurs or Baboon lemurs are an extinct type of lemurs that includes one family, Archaeolemuridae, two genera and three species. Despite their common names, members of Archaeolemuridae were not as closely related to monkeys as they were to other lemurs....

s, palaeopropithecid

Palaeopropithecinae

The sloth lemurs is an extinct clade of lemurs that includes four genera. Despite their common names, members of Palaeopropithecidae were not closely related to sloths but were closely related to the other lemur species....

s, the structure consists of four teeth, but it consists of six teeth in all other lemurs except for the highly derived Daubentonia (Aye-aye

Aye-aye

The aye-aye is a lemur, a strepsirrhine primate native to Madagascar that combines rodent-like teeth and a special thin middle finger to fill the same ecological niche as a woodpecker...

), which has replaced the toothcomb with a single pair of continuously growing anterior teeth. The first lower premolar

Premolar

The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant, making eight premolars total in the mouth. They have at least two cusps. Premolars can be considered as a 'transitional tooth' during chewing, or...

 following the toothcomb is usually shaped like a typical canine tooth.

Most strepsirrhine species use the toothcomb in grooming

Social grooming

In social animals, including humans, social grooming or allogrooming is an activity in which individuals in a group clean or maintain one another's body or appearance. It is a major social activity, and a means by which animals who live in proximity can bond and reinforce social structures, family...

, raking it through their fur or the fur of a compatriot. However, there are three known species that use their toothcombs to scrape trees for gum: the Masoala fork-marked lemur, the Verreaux's sifaka

Verreaux's Sifaka

Verreaux's sifaka , or white sifaka, is a medium sized primate in one of the lemur families, Indriidae. It lives in Madagascar and can be found in a variety of habitats from rainforest to western Madagascar dry deciduous forests and dry and spiny forests...

, and the Pygmy slow loris

Pygmy Slow Loris

The pygmy slow loris is a rare species of loris found in the tropical dry forests of Vietnam, Laos, southern China, and east of the Mekong River in Cambodia....

.

The first fossil strepsirrhine found to exhibit a toothcomb was Karanisia clarki, an extinct species of loris

Loris

Loris is the common name for the strepsirrhine primates of the subfamily Lorisinae in family Lorisidae. Loris is one genus in this subfamily and includes the slender lorises, while Nycticebus is the genus for the slow lorises....

 dating to the Middle Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 (c. 40 million years ago) and found in Egypt. This find, along with the lack of lemur fossils in Madagascar and Africa, has complicated the puzzle of lemur origins and diversification. Adapoids, from which modern strepsirrhines evolved, lacked toothcombs. By the Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, toothcombs seem to be the rule among strepsirrhines.

There was debate in the past over the cause for the evolution of the strepsirrhine toothcomb. It was argued at one point that the toothcomb evolved as a scraping tool to obtain gum from trees, but this idea has been generally discredited and replaced with the idea that it evolved as a grooming tool, just as it is used today.