Spalacids Temporal range: Early Miocene–Recent |
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Lesser Bamboo Rat, Cannomys badius | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Rodentia |
Superfamily: | Muroidea |
Family: | Spalacidae Gray, 1821 |
Subfamilies | |
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 south-eastern Europe. It includes the blind mole rats, bamboo rats, root rats, and zokors. This family represents the oldest split (excluding perhaps the Platacanthomyinae) in the muroid superfamily, and comprises animals adapted to a subterranean way of life. It was thought that these rodents evolved adaptations to living underground independently until recent genetic studies demonstrated that they form a monophyletic group. Members of the Spalacidae are often placed in the family Muridae along with all other members of the Muroidea.
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Characteristics
Spalacids are mouse to rat sized rodents, adapted to burrowing and living underground. They have short limbs, wedge-shaped skulls, strong neck muscles, large incisor teeth, and small eyes and external ears. In the zokors, which dig primarily with their feet, rather than their teeth, the front claws are also massively enlarged. These features are least extreme in the bamboo rats, which spend at least some of their time above ground, foraging for food. They are most highly developed in the blind mole rats, whose eyes are completely covered by skin, and entirely lack external ears or tails.
All of the spalacid species dig extensive underground burrows, which may include storage chambers for food, latrine chambers, breeding nests, and so on. They are generally solitary animals, and do not share their tunnel complexes with other individuals. All the species are herbivores, feeding on roots, bulbs, and tubers.
They give birth to litters of up to six young after a gestation period of between three and seven weeks, depending on the species. As with many other muroids, the young are born blind, hairless, and helpless. They may stay with the mother for several months before setting off to establish their own burrows, although some species disperse as soon as they are weaned.[1]
Technical Characters
Norris et al.[2] listed several characteristics that are present in all members of this family and that distinguish them from the rest of the muroids, (the clade Eumuroida). These are "the reduction or absence of external eyes, reduced pinnae, stocky body, short tail (<50% head and body length), broad rostrum, triangular-shaped braincase, infraorbital canal ovoid shape and does not extend ventrally to the roof of the palate, zygomatic plate absent or much reduced, nasolacrimal canal inside infraorbital canal, incisive foramina small to medium-sized, extensive neck musculature and prominent points of attachment on the occipitum, minimal reduction in M3 relative to M1 and M2, and a distinct orientation of the manubrium of the malleus bone."
Classification
The Spalacids are classified in three subfamilies, six genera, and 37 species.
FAMILY SPALACIDAE
- Subfamily Myospalacinae - Zokors
- Genus Myospalax
- Myospalax myospalax species group
- False Zokor, Myospalax aspalax
- Siberian Zokor, Myospalax myospalax
- Myospalax psilurus species group
- Transbaikal Zokor, Myospalax psilurus
- Myospalax myospalax species group
- Genus Eospalax
- Chinese Zokor, Eospalax fontanierii
- Rothschild's Zokor, Eospalax rothschildi
- Smith's Zokor, Eospalax smithii
- Genus Myospalax
- Subfamily Rhizomyinae
- Tribe Rhizomyini - Bamboo Rats
- Genus Rhizomys
- Hoary Bamboo Rat, Rhizomys pruinosus
- Chinese Bamboo Rat, Rhizomys sinensis
- Large Bamboo Rat, Rhizomys sumatrensis
- Genus Cannomys
- Lesser Bamboo Rat, Cannomys badius
- Genus Rhizomys
- Tribe Tachyoryctini
- Genus Tachyoryctes - Mole rats
- Ankole Mole Rat, Tachyoryctes ankoliae
- Mianzini Mole Rat, Tachyoryctes annectens
- Audacious Mole Rat, Tachyoryctes audax
- Demon Mole Rat, Tachyoryctes daemon
- Kenyan African Mole Rat, Tachyoryctes ibeanus
- Big-headed Mole Rat, Tachyoryctes macrocephalus
- Naivasha Mole Rat, Tachyoryctes naivashae
- King Mole Rat, Tachyoryctes rex
- Ruanda Mole Rat, Tachyoryctes ruandae
- Rudd's Mole Rat, Tachyoryctes ruddi
- Embi Mole Rat, Tachyoryctes spalacinus
- East African Mole Rat, Tachyoryctes splendens
- Storey's African Mole Rat, Tachyoryctes storeyi
- Genus Tachyoryctes - Mole rats
- Tribe Rhizomyini - Bamboo Rats
- Subfamily Spalacinae
- Genus Spalax - Blind mole rats
- Sandy Mole Rat, Spalax arenarius
- Mt. Carmel Blind Mole Rat, Spalax carmeli
- Middle East Blind Mole Rat, Spalax ehrenbergi
- Upper Galilee Mountains Blind Mole Rat, Spalax galili
- Giant Mole Rat, Spalax giganteus
- Golan Heights Blind Mole Rat, Spalax golani
- Balkan Mole Rat, Spalax graecus
- Judean Mountains Blind Mole Rat, Spalax judaei
- Lesser Mole Rat, Spalax leucodon
- Greater Mole Rat, Spalax microphthalmus
- Munzur Mole Rat, Spalax munzuri
- Nehring's Blind Mole Rat, Spalax nehringi
- Kazakhstan Blind Mole Rat, Spalax uralensis
- Podolsk Mole Rat, Spalax zemni
- Genus Spalax - Blind mole rats
References
- ^ Corbet, Gordon (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 666–671. ISBN 0-87196-871-1.
- ^ Norris, R.W. et al. (2004). "The phylogenetic position of the zokors (Myospalacinae) and comments on the families of muroids (Rodentia)". Molecular Phylogenetics and Evolution 31 (3): 972–978. DOI:10.1016/j.ympev.2003.10.020. PMID 15120394.
- Jansa, S. A. and M. Weksler. 2004. Phylogeny of muroid rodents: relationships within and among major lineages as determined by IRBP gene sequences. Molecular Phylogenetics and Evolution, 31:256-276.
- Michaux, J., A. Reyes, and F. Catzeflis. 2001. Evolutionary history of the most speciose mammals: molecular phylogeny of muroid rodents. Molecular Biology and Evolution, 17:280-293.
- 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.
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