The

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 Mandible, lower jaws. About 40% of all mammal specie ...

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 (biology), 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 ...

, but are part of the large and complex superfamily

Muroidea The Muroidea are a large Taxonomic rank, superfamily of rodents, including mice, rats, voles, hamsters, lemmings, Gerbillinae, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitat ...

. The platacanthomyids can be distinguished from the true dormice, because they have no

premolar The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

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

. 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. to describe a group of muroid rodents (mice, rats and relatives). The clade is not defined in the standard taxonomic hierarchy, but it is between superfamily and family. The Eumuroida ...

(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 artery t ...

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 sep ...

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 (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

– '' 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. The northwest Vietnamese form '' Typhlomy ...

''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 A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

Taxonomy

*Family Platacanthomyidae **Genus †'' Neocometes'' ***†'' Neocometes brunonis'' ***†'' Neocometes orientalis'' ***†'' Neocometes similis'' **Genus ''

'' (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 ''

'' (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. The northwest Vietnamese form '' Typhlomy ...

'' (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. The northwest Vietnamese form '' Typhlomy ...

'' ***†''

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. The northwest Vietnamese form '' Typhlomy ...

'' ***†'' Typhlomys intermedius'' ***†'' Typhlomys macrourus'' ***†'' Typhlomys primitivus''

Taxonomy

References

Further reading