Afrotheria

From Freepedia

Afrotheria are a clade of mammals with the rank of cohort, that has been proposed based on DNA analysis. Afrotheria are believed to have originated in Africa at a time when the continent was isolated from other continents. Their only externally visible common characteristic is the movable snout, although there is no convincing evidence that this structure is in fact homologous across all members of this group. The clades contained in Afrotheria are:

• Paenungulata: elephants, Sirenia and hyraxes
• Afrosoricida: tenrecs and golden moles
• Tubulidentata: aardvarks
• Macroscelidea: elephant shrews

The biggest problem with considering Afrotherians as an originally African clade is the fossil record. The earliest fossil evidence for African ungulates and elephant shrews are found outside Africa. The Afrotheres are part of the proposed clade Atlantogenata.

Afrotherian monophyly is not universally accepted, and morphological evidence places the elephants and their relatives as true ungulates. This may also be the case for the aardvarks and the elephant shrews, although not the tenrecs and golden moles, and the elephant shrews may be related to gnawing mammals (within Glires). A mammal known from Madagascar (Plesiorycteropus) is of unknown affinities but may also be an ungulate perhaps related to the mainland aardvark. Some morphological evidence does support the affinity of the tenrecs and golden moles to other Lipotyphlan insectivores, especially to Solenodon in the Caribbean region. This is a more traditional interpretaton of Tenrecomorph relationships.