''Phoberomys pattersoni'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

that lived in the ancient

Orinoco River The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers approximately 1 million km2, with 65% of it in Venezuela and 35% in Colombia. It is the List of rivers by discharge, f ...

delta around 8 million years ago. It was the second-largest of the roughly seven species of its genus. Like many other rodents, ''Phoberomys'' was a

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

with high-crowned

premolar The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

s and molars.

Description

An almost complete

skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...

was discovered in the Urumaco Formation at Urumaco,

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

, in 2000.''Phoberomys pattersoni''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org The new species was later classified with the name ''Phoberomys pattersoni'' in honor of palaeontologist Brian Patterson. Originally, ''Phoberomys pattersoni'' was estimated as being approximately 741 kg based on dimensions of the

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

, which at the time made it the largest known species of rodent, living or extinct. However, these estimates were criticized as being too large by later studies, which found that ''Phoberomys'' had an exceptionally thick femur relative to its body compared to other mammals. Body mass estimates based on skull length,

occipital condyle The occipital condyles are undersurface protuberances of the occipital bone in vertebrates, which function in articulation with the superior facets of the Atlas (anatomy), atlas vertebra. The condyles are oval or reniform (kidney-shaped) in shape ...

width, tooth row length, and femur length suggest ''Phoberomys'' weighed between , making it about the same size as a large

antelopes The term antelope refers to numerous extant or recently extinct species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do no ...

such as

greater kudu The greater kudu (''Tragelaphus strepsiceros'') is a large woodland antelope, found throughout East Africa, eastern and southern Africa. Despite occupying such widespread territory (animal), territory, they are sparsely populated in most areas d ...

and

waterbuck The waterbuck (''Kobus ellipsiprymnus'') is a large antelope found widely in sub-Saharan Africa. It is placed in the genus ''Kobus (antelope), Kobus'' of the family Bovidae. It was first Scientific description, described by Irish naturalist Will ...

. Although ''Phoberomys pattersoni'' was considered the largest known rodent at the time of its description, the discovery of a complete skull of ''

Josephoartigasia monesi ''Josephoartigasia'' is an extinct genus of enormous dinomyid rodent from the Early Pliocene to Early Pleistocene of Uruguay. The only living member of Dinomyidae is the pacarana. ''Josephoartigasia'' is named after Uruguayan national hero Jo ...

'' in 2008 showed this species to be even larger. ''Josephoartigasia'' was known at the time of ''P. pattersonis discovery (specifically, the species "''Artigasia magna''", now ''Josephoartigasia magna''), but the size of this rodent could not easily be determined because it was only known from jaw fragments and the teeth of ''Josephoartigasia'' are unusually small relative to its body size.

Description

References

Further reading