Science and conservation for the world’s 2800 small mammal species

Rodents: Family Spalacidae

holding_imgThe family Spalacidae is part of the superfamily Muroidea, which contains five other rodent families including Muridae and Cricetidae. Ancestors of Spalacidae first appeared in Asia during the Oligocene, with the family later appearing in the Miocene. During this time, the spalacids spread out underground, where they developed into the three modern subfamilies. These subfamilies then further radiated to their current locations. Spalacidae includes 3 subfamilies and 6 genera, which together include 36 species. The subfamilies are Myospalacinae including the genera Myospalax and Eospalax, Rhizomyinae including the genera Cannomys and Rhizomys, and Spalacinae including the genera Spalax. Species within the Spalacidae family include such animals as the zokors. Previously, Tachyoryctinae was a fourth subfamily, but recent molecular research has shown that the genus Tachyoryctes is in fact a sister group of Rhizomys, and has thus been incorporated into the subfamily Rhizomyinae.

Members of Spalacidae are found all throughout the Old World. Specifically, spalacids are found from Western to Eastern Europe, East Africa, the Middle East, and from China to Sumatra in Asia. Spalacids are either fossorial or semi-fossorial, and burrow in areas with damp soil, typically in grasslands or savannah. Members of Spalacidae are small to medium-sized rodents and have robust bodies, small eyes and limbs, and enlarged incisors. Though some species are naked, most members have a think coat of fur. The large front teeth serve as the primary mechanism for burrowing in all members except those belonging to Myospalacinae, which utilize limbs to dig underground. In addition to large incisors, spalacids also have hypsodont dentition, which indicates an herbivorous diet. Sexual dimorphism is not seen in most species. However, some species such as Tachyoryctes splendens exhibit larger males than females. In addition to large incisors, certain Spalacids have developed other adaptations to a subterranean lifestyle. Members of the genus Spalax have tumor suppressors that counteract cell death, which can occur when the body receives little oxygen. These tumor suppressants have been found to prevent and halt cancer development in organisms. Research is currently being conducted to find possible drug applications of these suppressants.

 

 

Work Cited
Honeycutt, R. et al. “The phylogenetic position of the zokors (Myospalacinae) and comments on the families of muroids (Rodentia).” Molecular Phylogenetics and Evolution 31.3 (2004): 972-978.
Poor, A. 2005. “Spalacidae blind mole rats, African mole rats, zokors, and bamboo rats” (Online). Animal Diversity Web. Accessed March 29, 2015 at http://animaldiversity.org/accounts/Spalacidae/.
Lin et al. “Transcriptome sequencing and phylogenetic resolution within Spalacidae (Rodentia).” BMC Genomics 15.32 (2014).
Manov et al. “Pronounced cancer resistance in a subterranean rodent, the blind mole-rat, Spalax: in vivo and in vitro evidence.” BMC Biology 11.91 (2013).

Author: Anna Cole