Phoberomys is an extinct rodent genus and the largest rodent known to have lived. It is part of the South American infraorder Caviomorpha, which includes guinea pigs and capybaras. Fossils of Phoberomys have been found in Argentina, Brazil, and Venezuela, dating from the Late Miocene (11.6 million to 5.3 million years ago) and Early Pliocene (5.3 million to 3.6 million years ago) epochs. Its closest living relative is the pacarana ( Dinomys branickii ). Known from many fossils, including a nearly complete skeleton from Urumaco, Venezuela, Phoberomys looked similar to a capybara. It had a deep jaw and high-crowned teeth, which were adaptations for eating gritty plants. Its hind limbs were massive, while its front limbs were more slender, suggesting it usually had its center of gravity toward the back. It may have rested on its haunches while feeding, using its forelimbs to gather plant material. Phoberomys likely lived in wetlands and nearshore swamps, similar to the capybara.

When and where did Phoberomys live?

Phoberomys is an extinct rodent genus and the largest rodent known to have lived. Phoberomys fossils have been found in Argentina, Brazil, and Venezuela. These specimens date to the Late Miocene (11.6 million to 5.3 million years ago) and Early Pliocene (5.3 million to 3.6 million years ago) epochs. Phoberomys likely dwelled in wetlands and nearshore swamps, similar to its relative the capybara.

How big was Phoberomys compared to rodents today?

Phoberomys was the largest rodent ever to have lived. It existed during the Late Miocene and Early Pliocene epochs in South America. Phoberomys was similar in appearance to a capybara , the largest living rodent today, which weighs 35 to 66 kg (77 to 146 pounds). Phoberomys weighed an estimated 170–700 kg (370–1,540 pounds), depending on whether the estimate is based on teeth or bone size. Even the smallest estimate is much larger than the capybara. By comparison, the Bosavi woolly rat , one of the largest modern rats, reaches over 32 inches in length and weighs about 3 pounds.

What did Phoberomys eat?

Phoberomys was an extinct rodent that lived from the Late Miocene to the Early Pliocene epochs in South America. Based on its fossils, Phoberomys was superficially similar to a capybara . Phoberomys had a deep jaw with high-crowned teeth, which are adaptations for a gritty, herbivorous diet . It may have rested on its haunches while feeding, using its smaller forelimbs to gather plant material.

How do scientists learn about Phoberomys from fossils?

Scientists learn about Phoberomys , an extinct rodent genus, through fossils . These fossils, found in Argentina, Brazil, and Venezuela, date back to the Late Miocene and Early Pliocene epochs. The discovery of an almost complete skeleton in Urumaco, Venezuela, has been particularly valuable. By examining the skeleton, especially the femur, scientists estimate its weight, though the unusual limb structure makes estimations challenging. The teeth also provide clues, suggesting a gritty, herbivorous diet. The fossil evidence indicates that Phoberomys lived in wetlands and swamps, much like its relative, the capybara.

Why is Phoberomys important for understanding rodent evolution?

Phoberomys is important for understanding rodent evolution because it is the largest rodent ever to have lived. This extinct genus, belonging to the Caviomorpha infraorder, includes living guinea pigs, capybaras, and chinchillas, all restricted to South America. Phoberomys lived during the Late Miocene and Early Pliocene epochs in Argentina, Brazil, and Venezuela. Examination of its skeleton suggests it weighed around 700 kg (1,540 pounds), but other estimates based on teeth size put it at 170–330 kg (370–730 pounds). Its closest living relative is the pacarana. Fossils of Phoberomys have been found, including a nearly complete skeleton from Urumaco, Venezuela.

Phoberomys

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Phoberomys

fossil rodent genus

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What is Phoberomys?
Phoberomys is an extinct rodent genus and the largest rodent known to have lived. It is part of the South American infraorder Caviomorpha, which includes guinea pigs and capybaras. Fossils of Phoberomys have been found in Argentina, Brazil, and Venezuela, dating from the Late Miocene (11.6 million to 5.3 million years ago) and Early Pliocene (5.3 million to 3.6 million years ago) epochs. Its closest living relative is the pacarana (Dinomys branickii).

Known from many fossils, including a nearly complete skeleton from Urumaco, Venezuela, Phoberomys looked similar to a capybara. It had a deep jaw and high-crowned teeth, which were adaptations for eating gritty plants. Its hind limbs were massive, while its front limbs were more slender, suggesting it usually had its center of gravity toward the back. It may have rested on its haunches while feeding, using its forelimbs to gather plant material. Phoberomys likely lived in wetlands and nearshore swamps, similar to the capybara.
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When and where did Phoberomys live?
Phoberomys is an extinct rodent genus and the largest rodent known to have lived. Phoberomys fossils have been found in Argentina, Brazil, and Venezuela. These specimens date to the Late Miocene (11.6 million to 5.3 million years ago) and Early Pliocene (5.3 million to 3.6 million years ago) epochs. Phoberomys likely dwelled in wetlands and nearshore swamps, similar to its relative the capybara.
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How big was Phoberomys compared to rodents today?
Phoberomys was the largest rodent ever to have lived. It existed during the Late Miocene and Early Pliocene epochs in South America. Phoberomys was similar in appearance to a capybara, the largest living rodent today, which weighs 35 to 66 kg (77 to 146 pounds).

Phoberomys weighed an estimated 170–700 kg (370–1,540 pounds), depending on whether the estimate is based on teeth or bone size. Even the smallest estimate is much larger than the capybara. By comparison, the Bosavi woolly rat, one of the largest modern rats, reaches over 32 inches in length and weighs about 3 pounds.
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What did Phoberomys eat?
Phoberomys was an extinct rodent that lived from the Late Miocene to the Early Pliocene epochs in South America. Based on its fossils, Phoberomys was superficially similar to a capybara. Phoberomys had a deep jaw with high-crowned teeth, which are adaptations for a gritty, herbivorous diet. It may have rested on its haunches while feeding, using its smaller forelimbs to gather plant material.
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How do scientists learn about Phoberomys from fossils?
Scientists learn about Phoberomys, an extinct rodent genus, through fossils. These fossils, found in Argentina, Brazil, and Venezuela, date back to the Late Miocene and Early Pliocene epochs. The discovery of an almost complete skeleton in Urumaco, Venezuela, has been particularly valuable. By examining the skeleton, especially the femur, scientists estimate its weight, though the unusual limb structure makes estimations challenging. The teeth also provide clues, suggesting a gritty, herbivorous diet. The fossil evidence indicates that Phoberomys lived in wetlands and swamps, much like its relative, the capybara.
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1. Phoberomys
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Why is Phoberomys important for understanding rodent evolution?
Phoberomys is important for understanding rodent evolution because it is the largest rodent ever to have lived. This extinct genus, belonging to the Caviomorpha infraorder, includes living guinea pigs, capybaras, and chinchillas, all restricted to South America. Phoberomys lived during the Late Miocene and Early Pliocene epochs in Argentina, Brazil, and Venezuela. Examination of its skeleton suggests it weighed around 700 kg (1,540 pounds), but other estimates based on teeth size put it at 170–330 kg (370–730 pounds). Its closest living relative is the pacarana. Fossils of Phoberomys have been found, including a nearly complete skeleton from Urumaco, Venezuela.
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Phoberomys, extinct rodent genus, the largest rodent ever to have lived, that belongs to the infraorder Caviomorpha, a group restricted to South America that also includes living guinea pigs, capybaras, and chinchillas. Phoberomys has been recovered from several sites dating to the Late Miocene (11.6 million to 5.3 million years ago) and Early Pliocene (5.3 million to 3.6 million years ago) epochs in Argentina, Brazil, and Venezuela. Its closest living relative is the pacarana (Dinomys branickii), a slow-moving South American rodent.

Phoberomys is known from many fossils, including an almost complete skeleton from Urumaco, Venezuela. It was superficially similar in appearance to a capybara. Phoberomys had a deep jaw with hypsodont (high-crowned) teeth, both of which were adaptations for a gritty herbivorous diet. Its hind limbs were massive, but its front limbs were comparatively slender, suggesting that the animal’s centre of gravity was usually toward the back. In addition, it may have rested on its haunches while feeding, using its smaller forelimbs to gather plant material.

An examination of the skeleton of Phoberomys suggests that it weighed about 700 kg (1,540 pounds), much more than the largest living rodent, the capybara. This body mass estimate was based on the diameter of its femur, the weight-bearing bone in the hip. The American bison (Bison bison) at 320–900 kg (700–1,980 pounds) is approximately the same size. Normally, the femur provides a reliable estimate of an animal’s mass, but, because of the unusual asymmetry of this animal’s forelimbs and hind limbs, it may have supported proportionally more of its weight in the back. If so, then the 700-kg estimate may be too large. A body mass estimate based on the forelimb suggests that Phoberomys weighed about 440 kg (970 pounds), similar to a medium-sized moose (Alces alces). The asymmetry of the forelimbs and hind limbs also complicates this body mass estimate, since it may mean that a calculation based on forelimbs may be too small.

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Body mass estimates based on the size of the teeth put Phoberomys at 170–330 kg (370–730 pounds), about the size of a pygmy hippopotamus (Hexaprotodon liberiensis). These estimates are less certain than the ones based on limb bones because Phoberomys had an unusually specialized dentition that resists a reliable calculation of mass. Even the smallest estimate, however, is many times larger than the capybara, which ranges from 35 to 66 kg (77 to 146 pounds). Phoberomys lived in wetlands and nearshore swamps, similar to its relative the capybara. Ancient saltwater lagoons, freshwater swamps and rivers, and terrestrial savannas are recorded in the rock deposits at Urumaco.

Paul David Polly

Phoberomys

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