The Spalacidae, or spalacids, are a
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
of
rodent
Rodents (from Latin , 'to gnaw') are mammals of the 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 rodents. They are na ...
s in the large and complex
superfamily
SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...
Muroidea
The Muroidea are a large superfamily of rodents, including mice, rats, voles, hamsters, lemmings, gerbils, and many other relatives. Although the Muroidea originated in Eurasia, they occupy a vast variety of habitats on every continent except A ...
. They are native to eastern
Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
, the
Horn of Africa
The Horn of Africa (HoA), also known as the Somali Peninsula, is a large peninsula and geopolitical region in East Africa.Robert Stock, ''Africa South of the Sahara, Second Edition: A Geographical Interpretation'', (The Guilford Press; 2004), ...
, the
Middle East
The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
, and southeastern
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...
. It includes the
blind mole-rat
The blind mole-rats, also known as the fossorial or subterranean mole rats, are a subfamily (Spalacinae) of rodents in the family Spalacidae, found in eastern Europe and western & central Asia. The hystricognath mole-rats of the family Bathyergi ...
s,
bamboo rat
The bamboo rats are four species of rodents of the subfamily Rhizomyinae. They are the sole living representatives of the tribe Rhizomyini. All are found in South Asia, Southeast Asia and East Asia.
The species are:
*The Chinese bamboo rat, '' ...
s,
mole-rat Mole-rat or mole rat can refer to several groups of burrowing Old World rodents:
* Bathyergidae, a family of about 20 hystricognath species in six genera from Africa also called blesmols.
*'' Heterocephalus glaber'', the naked mole-rat.
* Spalaci ...
s, and
zokor
Zokors are Asiatic burrowing rodents resembling mole-rats. They include two genera: ''Myospalax'' and ''Eospalax''. Zokors are native to much of China, Kazakhstan, and Siberia, Siberian Russia.
Traditionally, zokors were thought to be closely ...
s. This family represents the oldest split (excluding perhaps the
Platacanthomyidae
The rodent 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, but are part of the large and complex superfamily Muroidea. ...
) in the muroid superfamily, and comprises animals adapted to a
subterranean way of life. These rodents were thought to have evolved adaptations to living underground independently until recent genetic studies demonstrated they form a
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
group. Members of the Spalacidae are often placed in the family
Muridae
The Muridae, or murids, are the largest family of rodents and of mammals, containing approximately 1,383 species, including many species of mice, rats, and gerbils found naturally throughout Eurasia, Africa, and Australia.
The name Muridae come ...
along with all other members of the Muroidea.
Characteristics
Spalacids are
mouse
A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...
- to
rat-sized rodents, adapted to burrowing and living underground. They have short limbs, wedge-shaped skulls, strong neck muscles, large
incisor
Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, whe ...
teeth, and small eyes and
external ear
The outer ear, external ear, or auris externa is the external part of the ear, which consists of the auricle (also pinna) and the ear canal. It gathers sound energy and focuses it on the eardrum (tympanic membrane).
Structure
Auricle
Th ...
s. In the zokors, which dig primarily with their feet, rather than their teeth, the front
claw
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus ...
s 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 burrows, which may include storage chambers for food,
latrine
A latrine is a toilet or an even simpler facility that is used as a toilet within a sanitation system. For example, it can be a communal trench in the earth in a camp to be used as emergency sanitation, a hole in the ground (pit latrine), or m ...
chambers, and breeding nests. They are generally solitary animals, and do not share their tunnel complexes with other individuals. All the species are
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s, feeding on
root
In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...
s, bulbs, and
tuber
Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...
s.
They give birth to litters of up to six young after a
gestation
Gestation is the period of development during the carrying of an embryo, and later fetus, inside viviparous animals (the embryo develops within the parent). It is typical for mammals, but also occurs for some non-mammals. Mammals during pregna ...
period 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
Weaning is the process of gradually introducing an infant human or another mammal to what will be its adult diet while withdrawing the supply of its mother's milk.
The process takes place only in mammals, as only mammals produce milk. The infan ...
.
Characteristics
Norris ''et al.''
listed several characteristics present in all members of this family which distinguish them from the rest of the muroids, (the
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
Eumuroida
The Eumuroida are a clade defined in 2004 by Steppan et al. that includes rats, mice and related species, though not all rodents; in other words, a specific group of muroid rodents. The clade is not defined in the standard taxonomic hierarchy, b ...
). These are "the reduction or absence of external eyes, reduced pinnae, stocky body, short tail (<50% head and body length), broad
rostrum
Rostrum may refer to:
* Any kind of a platform for a speaker:
**dais
**pulpit
* Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects
* Rostrum (ship), a form of bow on naval ships
* Ros ...
, triangular-shaped braincase,
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 arte ...
ovoid shape and does not extend
ventral
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...
ly to the roof of 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 sepa ...
,
zygomatic plate absent or much reduced, nasolacrimal canal inside
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 arte ...
,
incisive foramina
In the human mouth, the incisive foramen (also known as: "''anterior palatine foramen''", or "''nasopalatine foramen''") is the opening of the incisive canals on the hard palate immediately behind the incisor teeth. It gives passage to blood vesse ...
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
The malleus, or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations fro ...
bone."
Classification
The spalacids are classified in three
subfamilies
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
, six
genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
, and 37
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
.
Family Spalacidae
*Subfamily
Myospalacinae
Zokors are Asiatic burrowing rodents resembling mole-rats. They include two genera: '' Myospalax'' and '' Eospalax''. Zokors are native to much of China, Kazakhstan, and Siberian Russia.
Traditionally, zokors were thought to be closely relate ...
- zokors
**Genus ''
Myospalax
''Myospalax'' is a genus of rodents in the family Spalacidae. It contains these species of zokor:
* False zokor, ''M. aspalax''
*Siberian zokor
The Siberian zokor (''Myospalax myospalax'') is a species of rodent in the family Spalacidae. It i ...
''
***''Myospalax myospalax'' species group
****
False zokor, ''M. aspalax''
****
Siberian zokor
The Siberian zokor (''Myospalax myospalax'') is a species of rodent in the family Spalacidae. It is found in Kazakhstan and Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Nor ...
, ''M. myospalax''
***''Myospalax psilurus'' species group
****
Transbaikal zokor
The Transbaikal zokor (''Myospalax psilurus'') is a species of rodent in the family Spalacidae. It is found in China, Mongolia, and Russia
Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe ...
, ''M. psilurus''
**Genus ''
Eospalax
''Eospalax'' is a genus of rodents in the family Spalacidae. It contains these species:
*Chinese zokor
The Chinese zokor (''Eospalax fontanierii'') is a species of rodent in the family Spalacidae. It is endemic to China, ranging from Qinghai ...
''
***
Chinese zokor
The Chinese zokor (''Eospalax fontanierii'') is a species of rodent in the family Spalacidae. It is endemic to China, ranging from Qinghai Province eastwards to Beijing in steppe and alpine grasslands. Henri Milne-Edwards first described it in 1 ...
, ''E. fontanierii''
***
Rothschild's zokor, ''E. rothschildi''
***
Smith's zokor, ''E. smithii''
*Subfamily
Rhizomyinae
The rodent subfamily Rhizomyinae includes the Asian bamboo rats and certain of the African mole-rats. The subfamily is grouped with the Spalacinae and the Myospalacinae into a family of fossorial muroid rodents basal to the other Muroidea.
The ...
**Tribe
Rhizomyini - bamboo rats
***Genus ''
Rhizomys
''Rhizomys'', also known as bamboo rat, is a genus of rodents in the family Spalacidae. ''Rhizomys'' are all stocky burrowers with short, naked tails, and contains the following species:
* Hoary bamboo rat (''R. pruinosus'')
* Chinese bamboo ...
''
****
Hoary bamboo rat, ''R. pruinosus''
****
Chinese bamboo rat
The Chinese bamboo rat (''Rhizomys sinensis'') is a species of rodent in the family Spalacidae found in southern China, northern Myanmar, and northern Vietnam. Its habitat is bamboo thickets usually at high elevations, pine forests, and plantati ...
, ''R. sinensis''
****
Large bamboo rat
The large bamboo rat, Sumatran rat, or Indomalayan rat (''Rhizomys sumatrensis'') is a species of rodent in the family Spalacidae found in Cambodia, China, Indonesia, Laos, Malaysia, Myanmar, Thailand, and Vietnam. It is one of four species of ...
, ''R. sumatrensis''
***Genus ''
Cannomys''
****
Lesser bamboo rat
The lesser bamboo rat (''Cannomys badius'') is a species of rodent in the family Spalacidae. It is monotypic within the genus ''Cannomys''. It is found in Bangladesh, Bhutan, Cambodia, China, India, Myanmar, Nepal, and Thailand.
Description
T ...
, ''C. badius''
***†Genus ''
Brachyrhizomys
''Brachyrhizomys'' is an extinct genus of ground-dwelling herbivorous rodent that lived in Miocene to Pleistocene of China and India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-larges ...
'' (Miocene to Pleistocene)
**Tribe
Tachyoryctini
***Genus ''
Tachyoryctes
''Tachyoryctes'' is a genus of rodent in the family Spalacidae.
It contains the following species:
* Ankole African mole-rat (''T. ankoliae'')
* Mianzini African mole-rat (''T. annectens'')
* Aberdare Mountains African mole-rat (''T. audax'')
* D ...
'' - African mole-rats
****
Ankole African mole-rat
The Ankole mole-rat or Ankole African mole-rat (''Tachyoryctes ankoliae'') is a species of rodent in the family Spalacidae found in southwestern Uganda and northwestern Tanzania. Its natural habitats are moist savanna and arable land
Arable la ...
, ''T. ankoliae''
****
Mianzini African mole-rat
The Mianzini mole-rat or Mianzini African mole-rat (''Tachyoryctes annectens'') is a species of rodent in the family Spalacidae endemic to Kenya. Its natural habitats are dry savanna
A savanna or savannah is a mixed woodland- grassland (i. ...
, ''T. annectens''
****
Aberdare Mountains African mole-rat
The Aberdare Mountains African mole-rat (''Tachyoryctes audax'') is a species of rodent in the family Spalacidae endemic to Kenya. Its natural habitats are subtropical or tropical moist montane forests and subtropical or tropical high-altitude g ...
, ''T. audax''
****
Demon African mole-rat
The northeast African mole-rat (''Tachyoryctes splendens'') is a species of rodent in the family Spalacidae and is found in Ethiopia, Somalia, and northwest Kenya. Its natural habitats are subtropical or tropical moist montane forests, dry savann ...
, ''T. daemon''
****
Kenyan African mole-rat
The Kenyan African mole-rat or Kenyan mole-rat (''Tachyoryctes ibeanus'') is a species of rodent in the family Spalacidae. It is endemic to Kenya. Its natural habitats are dry savanna, moist savanna, arable land, pastureland, plantations, rural g ...
, ''T. ibeanus''
****
Big-headed African mole-rat
The big-headed African mole rat, (''Tachyoryctes macrocephalus''), also known as the giant root-rat, Ethiopian African mole rat, or giant mole rat, is a rodent species in the family Spalacidae.
It is endemic to Ethiopia's Bale Mountains. Its na ...
, ''T. macrocephalus''
****
Navivasha African mole-rat
The Naivasha African mole-rat (''Tachyoryctes naivashae'') is a species of rodent in the family Spalacidae. It is endemic to Kenya. Its natural habitats are subtropical or tropical moist montane forests, moist savanna, arable land, and pasturel ...
, ''Tachyoryctes naivashae''
****
King African mole-rat
The King African mole-rat,Musser and Carleton, 2005, p. 924 King mole-rat, or Alpine mole-rat, (''Tachyoryctes rex'') is a burrowing rodent in the genus ''Tachyoryctes'' of family Spalacidae. It only occurs high on Mount Kenya, where it is ...
, ''T. rex''
****
Rwanda African mole-rat
The Rwanda mole-rat (''Tachyoryctes splendens'') is a species of rodent in the family Spalacidae found in Burundi, the Democratic Republic of the Congo, and Rwanda. Its natural habitats are subtropical or tropical moist montane forests, subtrop ...
, ''T. ruandae''
****
Rudd's African mole-rat
Rudd's mole-rat (''Tachyoryctes ruddi'') is a species of rodent in the family Spalacidae. It is found in Kenya and Uganda. Its natural habitats are subtropical or tropical moist lowland forest, subtropical or tropical moist montane forest, subtro ...
, ''T. ruddi''
****
Embi African mole-rat
The Embi mole-rat (''Tachyoryctes spalacinus'') is a species of rodent in the family Spalacidae endemic to Kenya. Its natural habitats are subtropical or tropical moist montane forests, moist savanna, arable land, pastureland, plantations, and h ...
, ''T. spalacinus''
****
Northeast African mole-rat
The northeast African mole-rat (''Tachyoryctes splendens'') is a species of rodent in the family Spalacidae and is found in Ethiopia, Somalia, and northwest Kenya. Its natural habitats are subtropical or tropical moist montane forests, dry savann ...
, ''T. splendens''
****
Storey's African mole-rat
Storey's African mole-rat (''Tachyoryctes storeyi'') is a species of rodent in the family Spalacidae endemic to Kenya. Its natural habitat is subtropical or tropical dry lowland grassland.
Some taxonomic authorities consider it to be conspecific ...
, ''T. storeyi''
*Subfamily
Spalacinae
The blind mole-rats, also known as the fossorial or subterranean mole rats, are a subfamily (Spalacinae) of rodents in the family Spalacidae, found in eastern Europe and Western Asia, western & central Asia. The Hystricognathi, hystricognath mole ...
- blind mole-rats
**Genus ''
Spalax
''Spalax'' is a genus of rodent in the family Spalacidae, subfamily '' Spalacinae'' (blind mole-rats). It is one of two extant genera in the subfamily Spalacinae, alongside ''Nannospalax''.'
Species in this genus are found in eastern Europe ...
''
***
Mehely's blind mole-rat
Mehely's blind mole-rat (''Spalax antiquus'') is an endangered species of rodent in the family Spalacidae. It is endemic to Romania.
Taxonomy
Previously described in 1909 by Lajos Méhelÿ as a subspecies of the Balkan mole-rat (''S. graecus'' ...
'', S. antiquus''
***
Sandy blind mole-rat, ''S. arenarius''
***
Giant blind mole-rat, ''S. giganteus''
***
Bukovina blind mole-rat
The Bukovina blind mole-rat or (erroneously) the Balkan blind mole-rat (''Spalax graecus'') is a species of rodent in the family Spalacidae found in Romania, Moldova, and Ukraine.
Taxonomy
The specific epithet ''graecus'', as well as the re ...
, ''S. graecus''
***
Oltenia blind mole-rat, ''S. istricus'' (possibly
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
)
***
Greater blind mole-rat, ''S. microphthalmus''
***
Kazakhstan blind mole-rat, ''S. uralensis''
***
Podolsk blind mole-rat, ''S. zemni''
**Genus ''
Nannospalax
''Nannospalax'' is a genus of rodent in the family Spalacidae, found in eastern Europe and western Asia. It is one of two genera in the blind mole-rats (subfamily Spalacinae), alongside ''Spalax''. Members of this genus are also known as small-b ...
'' - small-bodied mole-rats
***Subgenus ''Nannospalax''
****
Middle East blind mole-rat
The Middle East blind mole-rat or Palestine mole-rat (''Nannospalax ehrenbergi'') is a species of rodent in the family Spalacidae.
Taxonomy
It was formerly classified in the genus ''Spalax'', but more recent phylogenetic evidence supports it a ...
or Palestine mole-rat, ''N. ehrenbergi''
***Subgenus ''Mesospalax''
****
Lesser blind mole-rat, ''N. leucodon''
****
Anatolian blind mole-rat or Nehring's blind mole-rat, ''N. xanthodon''
References
*Jansa, S. A. and M. Weksler. 2004. Phylogeny of muroid rodents: relationships within and among major lineages as determined by IRBP
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
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
In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of th ...
estimates of rapid radiations in muroid rodents based on multiple nuclear genes. Systematic Biology, 53:533-553.
{{Taxonbar, from=Q557935
Rodent families
Muroid rodents
Extant Miocene first appearances
Taxa named by John Edward Gray