Castoridae Fossil range: Late Eocene - Recent
American Beaver, Castor canadensis
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Rodentia Suborder: Castorimorpha Family: Castoridae Hemprich, 1820
Genera
†Migmacastor †Agnotocastor †Neatocastor †Anchitheriomys †Propalaeocastor †Oligotheriomys †Palaeocastor †Capacikala †Pseudopalaeocastor †Euhapsis †Fossorcastor †Priusaulax †Eucastor †Microdipoides †Nothodipoides †Monosaulax †Prodipoides †Dipoides †Castoroides †Procastoroides †Trogontherium †Boreofiber †Euronexomys †Youngofiber †Asiacastor †Palaeomys †Chalicomys †Steneofiber †Zamolxifiber †Romanofiber †Schreuderia †Sinocastor †Hystricops Castor

The family Castoridae contains the two living species of beaver and their fossil relatives. Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor. Rodentia is an order of Mammals also known as rodents, characterised by two continuously-growing incisors in the upper and lower jaws which must Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe

Contents 1 Characteristics 2 Evolution 3 Taxonomy 4 References 5 See also

Characteristics

Main article: Beaver

Castorids are medium sized mammals, although large compared with most other rodents. Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe They are semiaquatic, with sleek bodies and webbed hind feet, and are more agile in the water than on land. This is a list of organisms that spend part of their life cycle or of which part of their anatomy is underwater. Their tails are flattened and scaly, adaptations that help them manoeuvre in the water.

Castorids live in small family groups that each occupy a specific territory, based around a lodge and dam constructed from sticks and mud. A dam is a barrier that divides waters. Dams generally serve the primary purpose of retaining water while other structures such as Floodgates, Levees They are herbivores, feeding on leaves and grasses in the summer, and woody plants such as willow in the winter^[1]. They have powerful incisors and the typical rodent dental formula:

1. Incisors (from Latin incidere, "to cut" are the first kind of Tooth in Heterodont Mammals They are located in the Premaxilla Dentition is the development of Teeth and their arrangement in the Mouth. 0. 1-2. 3

1. 0. 1. 3

Evolution

The earliest castorids belong to the genus Agnotocastor,known from the late Eocene and Oligocene of North America and Asia (Rybczynski, 2007). Agnotocastor is an extinct member of the mammalian family Castoridae. The Eocene epoch (558 ± 02 - 339 ± 01 Ma) is a major division of the Geologic timescale and the second epoch of the Palaeogene period in The Oligocene is a geologic epoch of the Paleogene period and extends from about 33 Other early castorids included genera such as Steneofiber, from the Oligocene and Miocene of Europe, the earliest member of the subfamily Castorinae, which contains castorids closely related to living beavers (Korth, 2002). Steneofiber is an extinct Genus of Beaver from Eurasia. This small 30 cm (1 ft long creature probably lived in large Fresh water The Miocene is a geological epoch of the Neogene period and extends from about 23 Their teeth were not well suited to gnawing wood, suggesting that this habit evolved at a later point, but they do appear adapted to semi-aquatic living^[2]. Later, such early species evolved into forms such as Palaeocastor from the Miocene of Nebraska. Palaeocastor ('prehistoric beaver' is an extinct Genus of Beaver that lived in the North American Badlands during the late Oligocene The Miocene is a geological epoch of the Neogene period and extends from about 23 Nebraska ( is a state located on the Great Plains of the Midwestern United States and Palaeocastor was about the size of a muskrat, and dug corkscrew-shaped burrows up to 2. A corkscrew is a tool for drawing stopping corks from Wine Bottles Generally it consists of a pointed metallic Helix (often called the "worm" 5 metres (8 feet) deep.

Giant forms evolved in the Pleistocene, including Trogontherium in Europe, and Castoroides in North America. The Pleistocene ('plaɪstəsin is the epoch from 18 million to 10000 years BP covering the world's recent period Castoroides is an extinct genus of giant Beavers that lived in North America during the Pleistocene. The latter animal was as large as a black bear, yet had a brain only marginally larger than that of modern beavers. Its shape suggests that it would have been a good swimmer, and it probably lived in swampy habitats (Savage and Long, 1986). A swamp is a Wetland featuring temporary or permanent inundation of large areas of land by shallow bodies of water

Taxonomy

McKenna and Bell (1997) divided Castoridae into two subfamilies, Castoroidinae and Castorinae. More recent studies (Korth, 2002; Rybczynski, 2007) have recognized two additional subfamilies of basal castorids, Agnotocastorinae and Palaeocastorinae, which is followed here. Within the family, Castorinae and Castoroidinae are sister taxa (Korth, 2002; Rybczynski, 2007); they share a more recent common ancestor with each other than with members of the other two subfamilies. Both subfamilies include semiaquatic species capable of constructing dams (Rybczynski, 2007). This is a list of organisms that spend part of their life cycle or of which part of their anatomy is underwater. Palaeocastorinae includes beavers that are interpreted as fossorial (burrowing) (Rybczynski, 2007), as are nothodipoidins and Migmacastor (Korth, 2007b). A fossorial is an Organism adapted to digging and life underground such as the Badger, the Naked mole rat, and the mole salamanders Ambystomatidae Migmacastor is an extinct member of the Beaver family Castoridae, known from a single species Migmacastor procumbodens. The following taxonomy is based on Korth (2002, 2007a,b) and Rybczynski (2007), with preference given to the latter where the these differ.

• Family Castoridae
  • †Migmacastor
  • Subfamily †Agnotocastorinae (paraphyletic)
    • Tribe †Agnotocastorini
      • †Agnotocastor
      • †Neatocastor
    • Tribe †Anchitheriomyini
      • †Anchitheriomys
      • †Propalaeocastor
      • †Oligotheriomys
  • Subfamily †Palaeocastorinae
    • †Palaeocastor
    • †Capacikala
    • †Pseudopalaeocastor
    • Tribe †Euhapsini
      • †Euhapsis
      • †Fossorcastor
  • Subfamily †Castoroidinae
    • †Priusaulax (placement in Castoroidinae questionable)
    • Tribe †Nothodipoidini
      • †Eucastor
      • †Microdipoides
      • †Nothodipoides
    • Tribe †Castoroidini (paraphyletic)
      • †Monosaulax
      • †Prodipoides
      • †Dipoides
      • †Castoroides
      • †Procastoroides
    • Tribe †Trogontheriini
      • †Trogontherium
      • †Boreofiber
      • †Euronexomys
      • †Youngofiber
      • †Asiacastor
  • Subfamily Castorinae
    • †Palaeomys or †Chalicomys
    • †Steneofiber
    • †Zamolxifiber
    • †Romanofiber
    • †Schreuderia
    • †Sinocastor
    • †Hystricops
    • Castor - modern beavers

References

• Korth W. W. , 2002. Comments on the systematics and classification of the beavers (Rodentia, Castoridae) Journal of Mammalian Evolution 8(4):279-296.
• Korth W. W. , 2007a. A new genus of beaver (Rodentia, Castoridae) from the Miocene (Clarendonian) of North America and systematics of the Castoroidinae based on comparative cranial anatomy Annals of Carnegie Museum 76(2):117-134.
• Korth W. W. , 2007b. The skull of Nothodipoides (Castoridae, Rodentia) and the occurrence of fossorial adaptations in beavers Journal of Paleontology 81(6):1533-1537.
• McKenna, Malcolm C. , and Bell, Susan K. 1997. Classification of Mammals Above the Species Level. Columbia University Press, New York, 631 pp. ISBN 0-231-11013-8.
• Rybczynski N. , 2007. Castorid phylogenetics: implications for the evolution of swimming and tree-exploitation in beavers Journal of Mammalian Evolution 14(1):1-35.
• Savage, R. J. G. , and Long, M. R. 1986. Mammal Evolution: an Illustrated Guide. Facts on File, New York, pp. 120-121 ISBN 0-8160-1194-X.

See also

• Beaver

Beavers are two primarily nocturnal semi-aquatic species of Rodent, one native to North America and one to Europe

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