King Mole Rat
Encyclopedia
Tachyoryctes rex, also known as the King African Mole Rat or Alpine Mole Rat, is a burrowing rodent
in the genus Tachyoryctes
of family Spalacidae
. It only occurs high on Mount Kenya
, where it is common. Originally described as a separate species related to T. audax in 1910, some classify it as the same species as T. splendens.
It is a very large, brownish species, with head and body length ranging from 222 to 268 mm (8.7 to 10.6 in). The young are dark with irregular white patches on their underparts. The animal builds large burrows and perhaps associated mounds and eats plant roots.
while on the Smithsonian African Expedition led by Theodore Roosevelt
. The next year, Edmund Heller
described the species as Tachyoryctes rex; he thought it most closely related to another Kenyan species, T. audax. In 1919, Ned Hollister
provided additional information using more material, and affirmed the relationship between T. rex and T. audax. He noted that the two were similar in coloration, but that T. rex was much larger; according to Heller, T. audax is somewhat darker in color. Since 1974, some taxonomic works have included T. rex and many other Tachyoryctes species in T. splendens, though without evaluation of the distinctive characters of the previously recognized species. The 2009 IUCN Red List
follows this arrangement, but the 2005 third edition of Mammal Species of the World
describes T. rex as a "distinctive species".
is small, but it grows with wear in adulthood until reaching a maximum, after which it shrinks again. The iris
is dark gray-brown. In fourteen specimens, head and body length is 222 to 268 mm (8.7 to 10.6 in), tail length is 54 to 80 mm (2.1 to 3.1 in), hindfoot length is 29 to 33 mm (1.1 to 1.3 in), and skull (condylobasal) length is 47 to 57 mm (1.9 to 2.2 in).
In comparison to those of Tachyoryctes audax, the nasal bone
s are larger and have angles at the sides. T. annectens, which is nearly as large, has smaller teeth and nasals; in T. rex, the basioccipital is broader, and the back part of the mandible
(lower jaw) is better developed and has the capsule of the incisor
placed further to the front.
, Kenya, at 2,600 to 3,350 m (8,500 to 11,000 ft) altitude. It is common in a limited area, at the upper edge of the bamboo forest and lower edge of the moorland
. A female found on October 5 had a large embryo. T. rex builds large mounds with diameters up to 6 m (20 ft). Some have interpreted these mounds as being built by termites instead. From those mounds, burrows may extend up to 50 m (160 ft) and be up to 1 m (3 ft) deep. One chamber is used for urination and defecation and to store plant matter; it produces a substantial amount of heat. In other chambers, T. rex builds large nests of grass. The animal eats plant roots. Its presence results in a change in vegetation on the mounds, which have fewer grasses and more woody plants, either because the animal eats plant roots or because the soil is altered.
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
in the genus Tachyoryctes
Tachyoryctes
Tachyoryctes is a genus of rodent in the Spalacidae family.It contains the following species:* Ankole Mole Rat * Mianzini Mole Rat * Audacious Mole Rat...
of family Spalacidae
Spalacidae
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...
. It only occurs high on Mount Kenya
Mount Kenya
Mount Kenya is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian , Nelion and Point Lenana . Mount Kenya is located in central Kenya, just south of the equator, around north-northeast of the capital Nairobi...
, where it is common. Originally described as a separate species related to T. audax in 1910, some classify it as the same species as T. splendens.
It is a very large, brownish species, with head and body length ranging from 222 to 268 mm (8.7 to 10.6 in). The young are dark with irregular white patches on their underparts. The animal builds large burrows and perhaps associated mounds and eats plant roots.
Taxonomy
In 1909, J. Alden Loring collected the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
while on the Smithsonian African Expedition led by Theodore Roosevelt
Theodore Roosevelt
Theodore "Teddy" Roosevelt was the 26th President of the United States . He is noted for his exuberant personality, range of interests and achievements, and his leadership of the Progressive Movement, as well as his "cowboy" persona and robust masculinity...
. The next year, Edmund Heller
Edmund Heller
Edmund Heller was an American zoologist.Heller attended Stanford University in 1896 and finished his study of zoology with a Bachelor of Arts degree in 1901. From 1926 to 1928 he was curator of mammals at the Field Museum of Natural History in Chicago...
described the species as Tachyoryctes rex; he thought it most closely related to another Kenyan species, T. audax. In 1919, Ned Hollister
Ned Hollister
Ned Hollister was an American biologist primarily known for studying mammals. From 1916 until his death he was Superintendent of the National Zoological Park...
provided additional information using more material, and affirmed the relationship between T. rex and T. audax. He noted that the two were similar in coloration, but that T. rex was much larger; according to Heller, T. audax is somewhat darker in color. Since 1974, some taxonomic works have included T. rex and many other Tachyoryctes species in T. splendens, though without evaluation of the distinctive characters of the previously recognized species. The 2009 IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
follows this arrangement, but the 2005 third edition of Mammal Species of the World
Mammal Species of the World
Mammal Species of the World, now in its 3rd edition, is a standard reference work in zoology giving descriptions and bibliographic data for the known species of mammals.An updated Third Edition of Mammal Species of the World was published late in 2005:...
describes T. rex as a "distinctive species".
Description
Tachyoryctes rex is a very large species with fluffy fur. It is reddish brown above and lighter brown below. The tip of the snout and the throat are black, and an area around the mouth is white. The feet are brown, but the toes are white. The tail is dark above and off-white below. Males are larger than females. Young animals are dark-furred, with some irregular white areas on their underparts. In young animals, the crown area of the molarsMolar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
is small, but it grows with wear in adulthood until reaching a maximum, after which it shrinks again. The iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
is dark gray-brown. In fourteen specimens, head and body length is 222 to 268 mm (8.7 to 10.6 in), tail length is 54 to 80 mm (2.1 to 3.1 in), hindfoot length is 29 to 33 mm (1.1 to 1.3 in), and skull (condylobasal) length is 47 to 57 mm (1.9 to 2.2 in).
In comparison to those of Tachyoryctes audax, the nasal bone
Nasal bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....
s are larger and have angles at the sides. T. annectens, which is nearly as large, has smaller teeth and nasals; in T. rex, the basioccipital is broader, and the back part of the mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
(lower jaw) is better developed and has the capsule of the incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
placed further to the front.
Distribution, ecology, and behavior
Tachyoryctes rex is found on the western slope of Mount KenyaMount Kenya
Mount Kenya is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian , Nelion and Point Lenana . Mount Kenya is located in central Kenya, just south of the equator, around north-northeast of the capital Nairobi...
, Kenya, at 2,600 to 3,350 m (8,500 to 11,000 ft) altitude. It is common in a limited area, at the upper edge of the bamboo forest and lower edge of the moorland
Moorland
Moorland or moor is a type of habitat, in the temperate grasslands, savannas, and shrublands biome, found in upland areas, characterised by low-growing vegetation on acidic soils and heavy fog...
. A female found on October 5 had a large embryo. T. rex builds large mounds with diameters up to 6 m (20 ft). Some have interpreted these mounds as being built by termites instead. From those mounds, burrows may extend up to 50 m (160 ft) and be up to 1 m (3 ft) deep. One chamber is used for urination and defecation and to store plant matter; it produces a substantial amount of heat. In other chambers, T. rex builds large nests of grass. The animal eats plant roots. Its presence results in a change in vegetation on the mounds, which have fewer grasses and more woody plants, either because the animal eats plant roots or because the soil is altered.
Literature cited
- Anonymous. 1908. President Roosevelt's African trip (subscription required). Science 28(729):876–877.
- Darlington, J.P.E.C. 1985. Lenticular soil mounds in the Kenya highlands (subscription required). Oecologia 66(1):116–121.
- Hausman, L.A. 1920. Structural characteristics of the hair of mammals. The American Naturalist 54:496–523.
- Heller, E. 1910. Descriptions of seven new species of East African mammals. Smithsonian Miscellaneous Collections 56(9):1–5.
- Hollister, N. 1919. East African mammals in the United States National Museum. Part II. Rodentia, Lagomorpha, and Tubulidentata. United States National Museum Bulletin 99(2):1–184.
- Musser, G.G. and Carleton, M.D. 2005. Superfamily Muroidea. Pp. 894–1531 in Wilson, D.E. and Reeder, D.M. (eds.). Mammal Species of the World: a taxonomic and geographic reference. 3rd ed. Baltimore: The Johns Hopkins University Press, 2 vols., 2142 pp. ISBN 978-0-8018-8221-0
- Osborne, P.L. 2000. Tropical ecosystems and ecological concepts. Cambridge University Press, 464 pp. ISBN 9780521645232
- Roosevelt, T. 1910. African game trails: an account of the African wanderings of an American hunter-naturalist. Scribner, 529 pp.
- Rundel, P.W., Smith, A.P. and Meinzer, F.C. 1994. Tropical alpine environments: plant form and function. Cambridge University Press, 376 pp. ISBN 9780521420891
- Schlitter, D., Agwanda, B. and Corti, M. 2008. . In IUCN. IUCN Red List of Threatened Species. Version 2009.2. <www.iucnredlist.org>. Downloaded on March 20, 2010.