Hypsodont is a pattern of
dentition with high-crowned
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...
and enamel extending past the gum line, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are
cows
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...
and horses; all animals that feed on gritty, fibrous material. The opposite condition is called
brachydont
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
.
Evolution
Since the morphology of the hypsodont tooth is suited to a more abrasive diet, hypsodonty was thought to have evolved concurrently with the spread of grasslands. Grass contains phytoliths, silica-rich granules, which wear away dental tissue more quickly. Analysis has shown however, that the development of this morphology is out of sync with the flourishing of grasslands. Instead, the ingestion of grit and soil is hypothesized to be the primary driver of hypsodonty (the
Grit, not grass hypothesis The grit, not grass hypothesis is an evolutionary hypothesis that explains the evolution of high-crowned teeth, particularly in New World mammals. The hypothesis is that the ingestion of gritty soil is the primary driver of hypsodont tooth developm ...
).
Morphology
Hypsodont dentition is characterized by:
* high-crowned
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...
* A rough, flattish occlusal surface adapted for crushing and grinding
* Cementum both above and below the
gingiva
The gums or gingiva (plural: ''gingivae'') consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health.
Structure
The gums are part of the soft tissue lin ...
l line
* Enamel which covers the entire length of the body and likewise extends past the gum line
* The cementum and the enamel
invaginate
Invagination is the process of a surface folding in on itself to form a cavity, pouch or tube. In developmental biology, invagination is a mechanism that takes place during gastrulation. This mechanism or cell movement happens mostly in the vegeta ...
into the thick layer of dentin
A mammal may have exclusively hypsodont molars or have a mix of dentitions.
Examples
Hypsodonty is observed both in the fossil record and the modern world. It is a characteristic of large clades (equids) as well as subspecies level specialization. For example, the
Sumatran rhinoceros
The Sumatran rhinoceros (''Dicerorhinus sumatrensis''), also known as the Sumatran rhino, hairy rhinoceros or Asian two-horned rhinoceros, is a rare member of the family Rhinocerotidae and one of five extant species of rhinoceros. It is the o ...
and the
Javan rhinoceros
The Javan rhinoceros (''Rhinoceros sondaicus''), also known as the Javan rhino, Sunda rhinoceros or lesser one-horned rhinoceros, is a very rare member of the family Rhinocerotidae and one of five extant rhinoceroses. It belongs to the same ge ...
both have brachydont, lophodont cheek teeth whereas the
Indian rhinoceros
}
The Indian rhinoceros (''Rhinoceros unicornis''), also called the Indian rhino, greater one-horned rhinoceros or great Indian rhinoceros, is a rhinoceros species native to the Indian subcontinent. It is listed as Vulnerable on the IUCN Red Li ...
has hypsodont dentition.
Examples of extant animals with hypsodont dentition include:
*
Cows
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...
*
Horses
*
Deer
Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the re ...
At least two lineages of
allotheres,
Taeniolabidoidea
Taeniolabidoidea is a group of extinct mammals known from North America and Asia. They were the largest members of the extinct order Multituberculata, as well as the largest non-therian mammals. ''Lambdopsalis'' even provides direct fossil eviden ...
and
Gondwanatheria, developed hypsodont teeth, the latter being probably among the first mammals to be able to process grass.
Gondwanatheria
/ref>
See also
*Brachydont
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
*Lophodont
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
*Dental formula
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolog ...
*Polyphyodont
A polyphyodont is any animal whose teeth are continually replaced. In contrast, diphyodonts are characterized by having only two successive sets of teeth.
Polyphyodonts include most toothed fishes, many reptiles such as crocodiles and geckos, ...
External links
The Diversity of Cheek Teeth
References
{{reflist
Dentition types
Veterinary dentistry