| Pyrotheria Temporal range: Paleocene–Oligocene |
|
|---|---|
| Pyrotherium romeroi with the notoungulate Rhynchippus equinus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Subclass: | Theria |
| Infraclass: | Eutheria |
| Superorder: | ?†Meridiungulata |
| Order: | †Pyrotheria Ameghino, 1895 |
| Families | |
Pyrotheria is an order of extinct meridiungulate mammals. These mastodon-like ungulates include the genera Baguatherium, Carolozittelia, Colombitherium, Gryphodon, Propyrotherium, Proticia, and Pyrotherium.[1]
They had the appearance of large, digitigrade, tapirlike mammals with relatively short, slender limbs and five-toed feet with broad, flat phalanges. Their fossils are restricted to Paleocene through Oligocene deposits of Brazil, Peru and Argentina.
Some experts place the clade Xenungulata, containing the monospecific genus Carodnia within Pyrotheria. The dentition is complete with strong, procumbent, chisel-shaped incisors, strong sharp-pointed canines, and low-crowned cheek teeth with bilophodont molars. The affinities of the Xenungulata remain uncertain. Affinities with the Dinocerata are strongly supported by the dental characteristics. Initial study of the structure of the tarsus suggested that the xenungulates had common ancestry with typical pyrotheres such as Pyrotherium,[2] but a more recent examination of the tarsus of Pyrotherium failed to support this, instead showing some traits shared by Pyrotherium and the Embrithopoda.[3] It remains to be seen which of these views will turn out to be right. This means that the Pyrotheria can be members of no less than three major cladistic branches of placential mammals: Meridiungulata (if xenungulates are the closest relatives), Laurasiatheria (if dinoceratans are the closest relatives) and Afrotheria (if embrithopods are the closest relatives).