| Pleurostylodon Temporal range: Middle Eocene ~ | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | † Notoungulata |
| Family: | † Isotemnidae |
| Genus: | † Pleurostylodon Ameghino 1897 |
| Type species | |
| †Pleurostylodon modicus Ameghino, 1897 | |
| Species | |
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| Synonyms | |
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Pleurostylodon is an extinct genus of notoungulate belonging to the family Isotemnidae. It lived during the Middle Eocene, in what is now Argentina.
This genus is known from numerous remains, mainly cranial, allowing to reconstruct its morphology. It was approximately the size of a dog, with an appearance evocating a tapir or a boar.
Pleurostylodon had a large skull, widening in the orbital arch area, and narrowing in the posterior area of the muzzle, whose terminal part was enlarged and had small incisors ; there was no diastema after the canines. The muzzle was shorter than in more derived and specialized toxodonts such as Adinotherium , and the occipital area was narrower. Several characteristics of its maxilla, of its teeth and of its unspecialized auditory region evocates Homalodotherium .
The third upper incisor was enlarged, and vaguely resembling a canine, while the canine was larger and lanceolate. The premolars and molars had an external edge outside the sinuous protoloph, with a strong parastyle and a fold of the paracon. The protoloph and metaloph were complete, except in the first upper premolar, while the protocon and the hypocon were separated in the non-worn teeth. A sort of hook and several small crests were present in variable numbers in the median valley of the molars.
The genus Pleurostylodon was first described in 1897 by Florentino Ameghino, based on fossil remains found in Argentina in Middle Eocene terrains. The type species is Pleurostylodon modicus, but Ameghino described numerous other species in subsequent years, including P. complanatus, P. crassiramis, P. recticrista, P. similis.
Pleurostylodon is one of the better known genera of the family Isotemnidae, a group of basal notoungulates comprising numerous relatively unspecialized genera of variable size. The Isotemnidae family is considered by some to be paraphyletic, in which case Pleurostylodon may be closer to the basis of Toxodontia, which includes various derived genera such as Toxodon .
Pyrotherium is an extinct genus of South American ungulate, of the order Pyrotheria, that lived in what is now Argentina and Bolivia, during the Late Oligocene. It was named Pyrotherium because the first specimens were excavated from an ancient volcanic ash deposit. Fossils of the genus have been found in the Deseado and Sarmiento Formations of Argentina and the Salla Formation of Bolivia.
Prosotherium is an extinct genus of hegetotheriid notoungulate. It lived during the Late Oligocene, and its fossilized remains were found in South America.
Propyrotherium is an extinct genus of mammals, belonging to the order Pyrotheria. It lived during the Late Eocene, in what is now South America.
Henricosbornia is an extinct genus of henricosborniid notoungulate that lived from the Late Paleocene to the Middle Eocene of what is now Argentina and Brazil.
Eohyrax is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived during the Middle Eocene, and its remains were discovered in South America.
Pseudhyrax is an extinct genus of archaeohyracid notoungulate. It lived from the Late Eocene to the Early Oligocene, of what is now South America.
Transpithecus is an extinct genus of Notoungulates, belonging to the suborder Typotheria. It lived during the Middle Eocene in what is today South America.
Propachyrucos is an extinct genus of hegetotheriid notoungulate. It lived from the Late Oligocene to the Early Miocene, in what is today South America.
Isotemnus is an extinct genus of notoungulate belonging to the family Isotemnidae. It lived from the Late Paleocene to the Middle Eocene of what is now Argentina.
Periphragnis is an extinct genus of isotemnid notoungulates that lived from the Middle Eocene to the Early Oligocene in what is now Argentina and Chile.
Eomorphippus is an extinct genus of notohippid notoungulate that lived from the Late Eocene to the Early Oligocene in what is today South America.
Eurygenium is an extinct genus of notoungulate belonging to the family Notohippidae. It lived during the Late Oligocene in what is today South America.
Morphippus is an extinct genus of notohippid notoungulate that lived during the Middle to Late Oligocene in what is now South America.
Ancylocoelus is an extinct genus of mammal, belonging to the order Notoungulata. It lived during the Late Oligocene, in what is today Argentina, in South America.
Archaeopithecus is an extinct genus of notoungulate, belonging to the suborder Typotheria. It lived during the Middle Eocene, in what is today Argentina.
Oldfieldthomasia is an extinct genus of Notoungulate, probably related to the suborder Typotheria. It lived during the Middle Eocene, in what is today South America.
Ultrapithecus is an extinct genus of oldfieldthomasiid notoungulate that lived during the Middle Eocene of what is now Argentina.
Argyrohyrax is an extinct genus of interatheriid notoungulate that lived during the Late Oligocene, of what is now Argentina and Bolivia.
Notopithecus is an extinct genus of Notoungulate, belonging to the suborder Typotheria. It lived from the Middle to the Late Eocene and its fossilized remains were discovered in South America.
Glyptatelus is an extinct genus of glyptodont. It lived from the Late Eocene to the Middle Oligocene in what is now Argentina and Bolivia.
