tethytherians

Tethytherians are a proposed extinct group of mammals that lived during the Paleogene period. The name Tethytheria refers to the proposed ancestral relationship of these mammals to both elephants and sirenians (manatees and dugongs), suggesting a common ancestor that may have lived around the ancient Tethys Sea. This hypothesis is based on shared skeletal and dental characteristics, particularly those related to the skull and jaw structure, and the presence of certain dental patterns.

The primary members of this proposed clade are the Proboscidea, which includes elephants and their extinct relatives like mammoths and mastodons, and the Sirenia, the aquatic mammals that comprise manatees and dugongs. Some classifications also include the extinct Hyracoidea (hyraxes) within Tethytheria, placing them as the sister group to the Proboscidea and Sirenia. This broader grouping is sometimes referred to as Paenungulata, a term encompassing all three orders.

The evolutionary link between these groups, especially the apparent connection between terrestrial elephant ancestors and aquatic sirenians, is a significant area of study in paleontology. Evidence supporting Tethytheria comes from fossil records found across Africa, Eurasia, and North America. While the precise phylogenetic relationships continue to be refined through new fossil discoveries and molecular data, the concept of Tethytheria remains an important framework for understanding the diversification of these distinctive mammal lineages.