Hypsodont is a pattern of
dentition
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-physiolo ...
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, ...
and enamel extending past the gum line, providing extra material for wear and tear. Some examples of animals with hypsodont dentition are
cows and horses; all animals that feed on gritty, fibrous material. The opposite condition is called
brachydont.
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).
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, ...
* 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 l ...
l line
* Enamel which covers the entire length of the body and likewise extends past the gum line
* The cementum and the enamel
invaginate 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 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
*
Horses
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...
*
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 and
Gondwanatheria
Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa and Antarctica during the Upper Cretaceous through the Paleogene (and possibly much earlier, if '' Allostaf ...
, developed hypsodont teeth, the latter being probably among the first mammals to be able to process grass.
Gondwanatheria
/ref>
See also
* Brachydont
* Lophodont
*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