Josephoartigasia

Josephoartigasia monesi

• South America ( Uruguay)

Josephoartigasia monesi is an extinct rodent and belongs to the family of Dinomyidae ( "Terrible mice " ), including the still living Pacarana counts. It is the largest known rodent. Fossils of Josephoartigasia monesi were detected in South American films that are assigned to the Pliocene and possibly Pleistocene. The Style epithet " monesi " was chosen in honor of the Uruguayan paleontologist Álvaro Mones.

Locations

Fossils of Josephoartigasia monesi were found in 4-2 million year old strata of the San José Formation on the banks of the Rio de la Plata in Uruguay. It is believed that the family of Dinomyidae to 20 million years ago, first spreading in southern South America. The type Josephoartigasia monesi is the youngest member of the family.

Properties

It was found in the San Jose lineup a 53 -centimeter-long skull, which had in the pines unusually small molars. The approaches of the masticatory muscles, which are responsible for the grinding movements of the mandible were unusually weak for rodents. This close paleontologists Ernesto Blanco and Andres Rinderknecht that Josephoartigasia monesi has probably fed on plants and soft fruits. This would support the theory that the rodent lived in river deltas with rich vegetation.

Estimates of the weight go out of 1,211 kilograms. However, these calculations a large uncertainty range of 753 kilograms more or less. With this weight Josephoartigasia monesi would be twice as heavy as the previously named as the largest rodent Phoberomys pattersoni and 16 times heavier than the South American capybara with its up to 60 kilograms. Because of its huge body, the animal was probably busy all day, according to calculations of food intake in order to maintain its body temperature constant can.

Classification

Due to the skull features, such as a weakly pronounced zygomatic process of the frontal bone, the designed on strength of masticatory jaw bone, which opened backwards orbit and the toothless gap ( diastema ) between premolars and incisors, assigns one Josephoartigasia monesi rodents ( Rodentia ) to. The incisors of the species were about 30 inches long.