Eucastor Tortus
''Eucastor'' is an extinct genus of beaver-grouped rodents. Based on the available evidence of the foramina In anatomy and osteology, a foramen (;Entry "foramen"
in

Joseph Leidy
Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist. Leidy was professor of anatomy at the University of Pennsylvania, later was a professor of natural history at Swarthmore College and the director of scientific and educational programs at the Wagner Free Institute of Science. His book ''Extinct Fauna of Dakota and Nebraska'' (1869) contained many species not previously described and many previously unknown on the North American continent. At the time, scientific investigation was largely the province of wealthy amateurs. The Leidy Glacier in northwest Greenland was named by Robert Peary after him. Early life and family Joseph Leidy was born on September 9, 1823, to an established Philadelphia family of Pennsylvania Germans. His father, Philip, was a hatter; his mother, Catharine, died during childbirth when he was young. His father then married his wife's first cousin, Christiana Mellick. Leidy also ha ...
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Genus (biology)
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 nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus '' Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should clearly demons ...
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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 native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, whose i ...
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Foramen
In anatomy and osteology, a foramen (;Entry "foramen"
in
Merriam-Webster Online Dictionary
'. plural foramina, or foramens ) is an open hole that is present in extant or extinct

amniote

s. Foramina inside the

body

of

animals

typically allow

nerves

,

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Beaver
Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, hand-like front feet, webbed back feet and flat, scaly tails. The two species differ in the shape of the skull and tail and fur color. Beavers can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous, consuming tree bark, aquatic plants, grasses and sedges. Beavers build dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams impound water and lodges serve as shelters. Their infrastructure creates wetlands used by many other species, and because of their effect on other organisms in the ...
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Prehistoric Beavers
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ...
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Prehistoric Rodent Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ...
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