The
rodent
Rodents (from Latin , 'to gnaw') are mammals of the 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 rodents. They are na ...
family Platacanthomyidae, or Oriental dormice, includes the
spiny dormice and the
Chinese pygmy dormice. In spite of their appearance, these animals are not true
dormice
A dormouse is a rodent of the family Gliridae (this family is also variously called Myoxidae or Muscardinidae by different taxonomists). Dormice are nocturnal animals found in Africa, Asia, and Europe. They are named for their long, dormant hibe ...
, but are part of the large and complex
superfamily
SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...
Muroidea
The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent except A ...
. The platacanthomyids can be distinguished from the true dormice, because they have no
premolar
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...
s, giving them three cheek teeth, like their relatives, the Muroidea.
The evolutionary relationship of the Platacanthomyidae was uncertain until a molecular phylogenetic study found it to be the earliest extant lineage to branch within the superfamily
Muroidea
The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent except A ...
. They can be distinguished from both the family
Spalacidae
The Spalacidae, or spalacids, are a family of rodents in the large and complex superfamily Muroidea. They are native to eastern Asia, the Horn of Africa, the Middle East, and southeastern Europe. It includes the blind mole-rats, bamboo rats, m ...
and the
Eumuroida
The Eumuroida are a clade defined in 2004 by Steppan et al. that includes rats, mice and related species, though not all rodents; in other words, a specific group of muroid rodents. The clade is not defined in the standard taxonomic hierarchy, ...
(all non-spalacid and non-platacanthomyid muroids), by the distinct shape of their
infraorbital canal
The infraorbital canal is a canal found at the base of the orbit that opens on to the maxilla. It is continuous with the infraorbital groove and opens onto the maxilla at the infraorbital foramen. The infraorbital nerve and infraorbital arte ...
and by the presence of multiple
openings in the
palate
The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity.
A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sepa ...
of the skull. On the basis of these two characteristics, they have been considered to be distinct from all other muroids. More work is needed to determine the evolutionary position of this subfamily.
The Platacanthomyidae contain three
genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
– ''
Neocometes'', ''
Platacanthomys
The Malabar spiny dormouse (''Platacanthomys lasiurus'') is a species of muroid rodent endemic to the Western Ghats of India. It is the only extant species in the genus ''Platacanthomys'' and although resembling a dormouse, it is not closely r ...
'' (spiny dormice), and ''
Typhlomys
The Chinese pygmy dormouse, (''Typhlomys cinereus'') is a species of rodent of the family Platacanthomyidae found in China and Vietnam.
Subspecies
Musser and Carleton (2005) recognized five subspecies. While the northwest Vietnamese form '' Typh ...
''
[Jansa, S.A., T.C. Giarla, and B.K. Lim. 2009. The Phylogenetic Position of the Rodent Genus Typhlomys and the Geographic Origin of Muroidea. "Journal of Mammalogy": October 2009, Vol. 90, No. 5, pp. 1083-1094. ] (pygmy dormice) – but only three extant
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
.
Taxonomy
*Family Platacanthomyidae
**Genus †''
Neocometes''
***†''
Neocometes brunonis''
***†''
Neocometes orientalis''
***†''
Neocometes similis''
**Genus ''
Platacanthomys
The Malabar spiny dormouse (''Platacanthomys lasiurus'') is a species of muroid rodent endemic to the Western Ghats of India. It is the only extant species in the genus ''Platacanthomys'' and although resembling a dormouse, it is not closely r ...
'' (spiny dormice)
***†''
Platacanthomys dianensis
The Malabar spiny dormouse (''Platacanthomys lasiurus'') is a species of muroid rodent endemic to the Western Ghats of India. It is the only extant species in the genus ''Platacanthomys'' and although resembling a dormouse, it is not closely r ...
''
***''
Platacanthomys lasiurus
The Malabar spiny dormouse (''Platacanthomys lasiurus'') is a species of muroid rodent endemic to the Western Ghats of India. It is the only extant species in the genus ''Platacanthomys'' and although resembling a dormouse, it is not closely r ...
'' (spiny dormouse)
**Genus ''
Typhlomys
The Chinese pygmy dormouse, (''Typhlomys cinereus'') is a species of rodent of the family Platacanthomyidae found in China and Vietnam.
Subspecies
Musser and Carleton (2005) recognized five subspecies. While the northwest Vietnamese form '' Typh ...
'' (pygmy dormice)
***''
Typhlomys cinereus
The Chinese pygmy dormouse, (''Typhlomys cinereus'') is a species of rodent of the family Platacanthomyidae found in China and Vietnam.
Subspecies
Musser and Carleton (2005) recognized five subspecies. While the northwest Vietnamese form '' Typ ...
'' (Chinese pygmy dormouse)
***''
Typhlomys nanus
The Chinese pygmy dormouse, (''Typhlomys cinereus'') is a species of rodent of the family Platacanthomyidae found in China and Vietnam.
Subspecies
Musser and Carleton (2005) recognized five subspecies. While the northwest Vietnamese form '' Typ ...
''
***†''
Typhlomys hipparionium
The Chinese pygmy dormouse, (''Typhlomys cinereus'') is a species of rodent of the family Platacanthomyidae found in China and Vietnam.
Subspecies
Musser and Carleton (2005) recognized five subspecies. While the northwest Vietnamese form '' Typ ...
''
***†''
Typhlomys intermedius''
***†''
Typhlomys macrourus''
***†''
Typhlomys primitivus''
References
Further reading
* Musser, G. G. and M. D. Carleton. 2005. Superfamily Muroidea. pp. 894–1531 in ''Mammal Species of the World a Taxonomic and Geographic Reference''. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.
* Norris, R. W., K. Y. Zhou, C. Q. Zhou, G. Yang, C. W. Kilpatrick, and R. L. Honeycutt. 2004. The phylogenetic position of the zokors (Myospalacinae) and comments on the families of muroids (Rodentia). ''Molecular Phylogenetics and Evolution'', 31:972-978.
* Nowak, R. M. 1999. ''Walker's Mammals of the World'', Vol. 2. Johns Hopkins University Press, London.
* Steppan, S. J., R. A. Adkins, and J. Anderson. 2004. Phylogeny and divergence date estimates of rapid radiations in muroid rodents based on multiple nuclear genes. ''Systematic Biology'', 53:533-553.
{{Taxonbar, from=Q1073641
Muroid rodents
Rodent families
Extant Miocene first appearances
Taxa named by Edward Richard Alston