In
rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...
s, incisor procumbency refers to the orientation of the upper
incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, w ...
, defined by the position of the cutting edge of the incisor relative to the vertical plane of the incisors. Proodont incisors have the cutting edge in front of the vertical plane, orthodont teeth have it perpendicular to the plane, opisthodont incisors have it behind the plane, and hyper-opisthodont teeth have the cutting edge even behind the back of the
alveolus of the incisor.
Phyllotini are mostly opisthodont, but ''
Auliscomys'' and ''
Galenomys'' are orthodont and have sometimes even been described as proodont, and ''
Eligmodontia'', ''
Loxodontomys'', and some species of ''
Calomys'' are hyper-opisthodont. ''
Irenomys
''Irenomys tarsalis'', also known as the Chilean climbing mouse, Chilean tree mouse, or long-footed irenomys,Musser and Carleton, 2005, p. 1121 is a rodent found in Chile, from about 36° to 46°S, and in adjacent Argentina, mainly in forests. ...
'', ''
Reithrodon
''Reithrodon'' is a genus of rodent in the family Cricetidae.
It contains the following living species:
* Bunny rat (''Reithrodon auritus'')
* Naked-soled conyrat
The naked-soled conyrat (''Reithrodon typicus'') is a species of rodent in th ...
'', and ''
Neotomys'', formerly classified as phyllotines, are also hyper-opisthodont.
[Steppan, 1995, p. 18] Oryzomyini
Oryzomyini is a tribe of rodents in the subfamily Sigmodontinae of the family Cricetidae. It includes about 120 species in about thirty genera,Weksler et al., 2006, table 1 distributed from the eastern United States to the southernmost parts of ...
are also mostly opisthodont, but ''
Amphinectomys savamis'', ''
Handleyomys fuscatus'', ''
Melanomys caliginosus'', ''
Mindomys hammondi
''Mindomys'' is a genus of sigmodontine rodents in the family Cricetidae. It includes two species known only from Ecuador, Hammond's rice rat (''Mindomys hammondi'') and the Kutukú rat (''Mindomys kutuku'').
See also
* List of mammals of Ecuad ...
'', ''
Scolomys melanops'', and ''
Sigmodontomys aphrastus'' are orthodont.
[Weksler, 2006, p. 43]
References
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Literature cited
*Steppan, S.J. 1995. Revision of the tribe Phyllotini (Rodentia: Sigmodontinae), with a phylogenetic hypothesis for the Sigmodontinae. Fieldiana Zoology 80:1–112.
*Weksler, M. 2006
Phylogenetic relationships of oryzomyine rodents (Muroidea: Sigmodontinae): separate and combined analyses of morphological and molecular data Bulletin of the American Museum of Natural History 296:1–149.
Rodent anatomy