The Mexican volcano mouse (''Neotomodon alstoni'') is a species of

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 ...

in the family

Cricetidae The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, muskrats, and New World rats and mice. At almost 608 species, it is the second-largest family of mammals, a ...

endemic to high elevation areas of the

Trans-Mexican Volcanic Belt The Trans-Mexican Volcanic Belt ( es, Eje Volcánico Transversal), also known as the Transvolcanic Belt and locally as the (''Snowy Mountain Range''), is an active volcanic belt that covers central-southern Mexico. Several of its highest peaks h ...

Taxonomy and systematics

Merriam originally described the Mexican volcano mouse as one of three species in the genus ''Neotomodon''; ''N. alstoni'' was moved to the deer mouse genus '' Peromyscus'' in 1979, then subsequently moved back to ''Neotomodon''. Merriam does not state after whom the species is named in his original description for the genus (and species). Despite the current taxonomy, a recent phylogeny based on cytochrome-b sequences shows ''Peromyscus'' to be

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

, and the authors of that paper suggest ''Neotomodon'' (and several other monotypic genera) be transferred to ''Peromyscus''.

Distribution

The Volcano mouse is seen to reside restrictively to higher elevation or boreal habitats of the trans-volcanic belt of Central Mexico. There has been no discovery of the fossil record for this species but it seems to have a similarity in appearance to Pliotomodon' fossil. The mouse can perform simple burrowing in well-drained areas and sometimes pass under boulders.

Characteristics

The Volcano mouse has a relatively medium-sized compared to other members of its genus. It has a pair of broad, naked ears while its fur is rather soft with grayish to fulvous brown color dorsally and whitish ventrally. Its tail is quite short but sharply bicolored. Compared to its short brain case entrapped in a broad skull, its zygomatic expanded. Its molars are pretty large and densely enameled. No sexual dimorphism in this species. With relatively large eyes and ears, bi-colored body and tail (dark dorsally and white ventrally), and a tail slightly shorter than the body length, the Mexican volcano mouse appears very similar to a

deer mouse ''Peromyscus'' is a genus of rodents. They are commonly referred to as deer mice or deermice, not to be confused with the chevrotain or "mouse deer". They are New World mice only distantly related to the common house and laboratory mouse, ''Mu ...

, but it is diagnosed by several skull characters including the number and extent of palatal ridges and molar characteristics.

Life events

Mexican volcano mouse breeding is thought to occur between June and September, with two to three litters per year of 3.3 young per litter. The mouse exhibits bi-parental care in captivity, which suggests a monogamous mating system. Little is known about other life history characteristics of the species, for example, sex ratio, age at first breeding, etc. Male with high testosterone levels develop a paternal care which increases better chances of survival and growth of its offspring. This is put under study by captive pair of mouse during postpartum and weaning periods. The presence of male lead to females care less for the young. When both parents present, however, their offspring survival chance increases significantly.

Taxonomy and systematics

Distribution

Characteristics

Life events

References

Further reading