Castoroides leiseyorum (Giant Beaver) is an extinct species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Castoroides

Castoroides

Castoroides, or Giant Beaver, is an extinct genus of enormous beavers that lived in North America during the Pleistocene. There are two known species:*Castoroides leiseyorum...

 of the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Castoridae

Castoridae

The family Castoridae contains the two living species of beaver and their fossil relatives. This was once a highly diverse group of rodents, but is now restricted to a single genus, Castor.- Characteristics :...

, endemic to North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, more specifically the southeastern United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 ~2.1 million—11,000 years ago. See notes below.

C. leiseyorum and its northern sister species Castoroides ohioensis, were the largest beavers to ever exist. C. leiseyorum had a length

Length

In geometric measurements, length most commonly refers to the longest dimension of an object.In certain contexts, the term "length" is reserved for a certain dimension of an object along which the length is measured. For example it is possible to cut a length of a wire which is shorter than wire...

 close to 2.5 m (8.2 feet) and an estimated weight

Weight

In science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...

 of 60–100 kg (130-220 lbs).

Taxonomy

Castoroides leiseyorum was named by S. Morgan and J. A. White in 1995 for the Leisey family, phosphate

Phosphate

A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...

 quarry

Quarry

A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel. They are often collocated with concrete and asphalt plants due to the requirement...

 owners which found the first skull

Skull

The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

.

Fossil distribution

• Leisey Shell Pit 1A and 3B, Hillsborough County, Florida
  Hillsborough County, Florida
  As of the census of 2000, there were 998,948 people, 391,357 households, and 255,164 families residing in the county. The population density was 951 people per square mile . There were 425,962 housing units at an average density of 405 per square mile...
  
   paleontological sites ~2.1 Ma. Age is based on J. Alroy's evaluation
  Evaluation
  Evaluation is systematic determination of merit, worth, and significance of something or someone using criteria against a set of standards.Evaluation often is used to characterize and appraise subjects of interest in a wide range of human enterprises, including the arts, criminal justice,...
  
   on November 11, 2007.
• Strawberry Hill site, (Copper River
  Copper River
  Copper River may refer to:*Copper River , in the United States.*Copper River , in the United States.*Copper River , a tributary of the Skeena River in Canada....
  
   dredging) Charleston County, South Carolina
  Charleston County, South Carolina
  Charleston County is a county located in the U.S. state of South Carolina. According to a 2005 U.S. Census Bureau estimate, its population was 330,368. Its county seat is Charleston. It is the third-most populous county in the state . Charleston County was created in 1901 by an act of the South...
  
  . ~1.8 Ma—11,000 years ago.