Pygmy ground squirrels are small

ground squirrel Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...

s in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Xerospermophilus'', family

Sciuridae Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

, containing four species from Mexico and the United States. The members of this genus were formerly placed in the large ground squirrel genus ''

Spermophilus ''Spermophilus'' is a genus of ground squirrels in the Sciuridae, squirrel family. As traditionally defined the genus was very species-rich, ranging through Europe, Asia and North America, but this arrangement was found to be paraphyletic to ...

''. Since

DNA sequencing DNA sequencing is the process of determining the nucleic acid sequence – the order of nucleotides in DNA. It includes any method or technology that is used to determine the order of the four bases: adenine, guanine, cytosine, and thymine. Th ...

of the cytochrome ''b'' gene has shown ''Spermophilus'' to be

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

to the

prairie dog Prairie dogs (genus ''Cynomys'') are herbivorous burrowing ground squirrels native to the grasslands of North America. Within the genus are five species: black-tailed, white-tailed, Gunnison's, Utah, and Mexican prairie dogs. In Mexico, p ...

s and

marmot Marmots are large ground squirrels in the genus ''Marmota'', with 15 species living in Asia, Europe, and North America. These herbivores are active during the summer, when they can often be found in groups, but are not seen during the winter, ...

s, this group is now separated, along with six other genera. Within the genus, the

Mohave ground squirrel The Mohave ground squirrel (''Xerospermophilus mohavensis'') is a species of ground squirrel found only in the Mojave Desert in California. The squirrel was first described in 1886 by Frank Stephens of San Diego. It is listed as a threatened spe ...

and the

round-tailed ground squirrel The round-tailed ground squirrel (''Xerospermophilus tereticaudus''), known as "Ardillón cola redonda" in Spanish, live in the desert of the Southwestern United States and Northwestern Mexico. They are called "ground squirrels" because they bur ...

were thought to be close relatives, sometimes a

subgenus In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus. In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...

''Xerospermophilus'', while the

spotted ground squirrel The spotted ground squirrel (''Xerospermophilus spilosoma'') is a species of ground squirrel in the rodent family Sciuridae. It is found throughout Mexico and the central and western United States. Characterized by a white spotted back, the spott ...

and the Perote ground squirrel were placed in the subgenus (now a genus) ''

Ictidomys ''Ictidomys'' is a North American genus of rodent in the squirrel family, which contains the thirteen-lined ground squirrel, the Mexican ground squirrel, and the Rio Grande ground squirrel. These species were included in the species-rich groun ...

''. The name of the genus is a combination of the Greek word ''xeros'', "dry", and ''

'', which also comes from Greek, meaning "seed lovers".

Species

The four species in ''Xerospermophilus'' are listed below. These are the same species that were previously grouped in the subgenus ''Otospermophilus''. *

, ''Xerospermophilus mohavensis'' *

Round-tailed ground squirrel The round-tailed ground squirrel (''Xerospermophilus tereticaudus''), known as "Ardillón cola redonda" in Spanish, live in the desert of the Southwestern United States and Northwestern Mexico. They are called "ground squirrels" because they bur ...

, ''Xerospermophilus tereticaudus'' *

Spotted ground squirrel The spotted ground squirrel (''Xerospermophilus spilosoma'') is a species of ground squirrel in the rodent family Sciuridae. It is found throughout Mexico and the central and western United States. Characterized by a white spotted back, the spott ...

, ''Xerospermophilus spilosoma'' * Perote ground squirrel, ''Xerospermophilus perotensis''

References

Rodent genera Taxa named by Clinton Hart Merriam {{ground-squirrel-stub