Paleontologists from the Aïn Chock Faculty of Sciences at Hassan II University in Casablanca and the Museum of Paleontology at the University of Michigan in the United States have discovered, south of Dakhla, fossils of Sirenians – more commonly known as “cows of sea” – which date back to the geological era of the Upper Eocene, i.e. 35 to 40 million years ago.
A press release from Hassan IIC University specifies that these new Moroccan fossils have enabled Moroccan and American paleontologists to identify a new genus and a new species of Sirenians which they have baptized Dakhlasiren marocensis to teach from the place of discovery (Dakhla in Morocco) and the taxonomy of the animal (Sirenian) and to underline in passing the attachment of Dakhla to Morocco.
Sea cows or Sirenia are marine mammals that today include the manatee and dugong that inhabit shallow tropical waters, primarily in the southern hemisphere.
The three current species of manatee live along the Atlantic coasts and in rivers of Latin America and West Africa; the dugong lives in the Indian and Pacific (southwest) oceans, the statement noted.
These present-day forms are relics of a largely extinct order that culminated in the Miocene (-24 to -5.3 million years ago), a period of warm global climate coinciding with extensive warm, shallow coastal marine habitats.
Note that sirenians are the only existing herbivorous marine mammals and the only herbivorous mammals to have become exclusively aquatic, the statement adds, noting that sirenians, like cetaceans, are interesting from a macroevolutionary point of view because they are descendants terrestrial mammals that have evolved to become fully aquatic.
Both groups (Sirenians and Cetaceans) transitioned from adaptation from terrestrial to aquatic life independently during the early to mid-Eocene (about 50–30 million years ago).