Afrotheria

Afrotheria is a special group of mammals that mostly live in or come from Africa. This group includes animals like golden moles, elephant shrews, otter shrews, tenrecs, aardvarks, hyraxes, elephants, and sea cows. Even though these animals look very different from each other, scientists discovered they are all related because of studies of their genes.

Long ago, Africa was separated from other landmasses by water. Because of this, many types of mammals that lived on other continents could not get to Africa. Instead, the animals that were already in Africa, the afrotheres, evolved to fill the same roles as those other mammals. For example, small afrotheres like elephant shrews acted like insectivores, hyraxes acted like rodents, and aardvarks acted like animals that eat ants found on other continents.

Scientists did not know that all these animals were closely related until the late 1990s. Before that, they thought these animals belonged to different groups. But now, we know they all share a common ancestor and are part of the afrotheres.

Evolutionary relationships

Scientists first suggested the group called Afrotheria in 1998 by looking at DNA. Before that, some studies from the 1920s to the 1990s hinted that some African mammals might be closely related. The group includes elephants, sea cows, hyraxes, tenrecs, golden moles, sengis, and aardvarks.

Studies using both DNA and body features show that these animals share a common ancestor not shared with other mammals. They often have more vertebrae, special ankle bones, and late-growing teeth. DNA studies also support this group. Afrotheria is one of the three main groups of placental mammals. Scientists think this group began to form about 105 million years ago when Africa was separated from other land masses.

Phylogeny

Current status and distribution

Many living members of Afrotheria face a high risk of disappearing, which would be a big loss for genetic and evolutionary variety. The IUCN Afrotheria Specialist Group points out that Afrotheria includes nearly a third of all mammalian orders in Africa and Madagascar, but only 75 of more than 1,200 mammalian species in these areas.

While most Afrotheria species live in Africa, some, like the Indian elephant and three of the four sirenian species, are found in other places and are also in danger. Before the Quaternary extinction event, animals like proboscideans lived on every continent except Australia and Antarctica. Hyraxes lived in much of Eurasia as recently as the end of the Pliocene. Some extinct groups of afrotheres, such as embrithopods and desmostylians, were once found far and wide. However, desmostylians might actually belong to a different group called perissodactyls, though this is still being debated. The exact group for embrithopods is also unclear.

Classification

Afrotheria is a group of mammals that mostly live in Africa. This group includes animals like aardvarks, elephant shrews, tenrecs, golden moles, hyraxes, elephants, and sea cows. Scientists have learned about these connections mostly by studying their genes.

Some of these animals belong to groups that are only found in Africa, showing that Africa was a special place for these animals to live and evolve.