An international team of scientists has discovered fossils of Serenia, more commonly known as “sea cows”, which date back to the geological age of the late Eocene, that is, 35 to 40 million years ago, in the south of the city of Dakhla in the Sahara region.
Paleontologists from the Faculty of Sciences of Ain Chak at Hassan II University in Casablanca, from the Museum of Paleontology of the University of Michigan in the United States, and the Department of Paleontology in Saudi Arabia participated in the study. Results In the “Journal of African Earth Sciences” on March 11th.
Samir Zuhri, a member of the research team from Morocco and professor of higher education at the Department of Geology (Palaeontology) at Hassan II University, told Al Jazeera Net via e-mail: From a scientific point of view, this study sheds new light on the evolution of this group of dugongs that are cousins to elephants. It originated in the African continent before spreading to all regions with a warm climate and deep shallow waters, which it called “Dakhlasiren marocensis”.
According to the unpublished press release of the study obtained by Al Jazeera Net from the researcher, these new Moroccan excavations enabled Moroccan and American paleontologists to identify a new gender and type of serines that they called “Dakhlaseren Maroconsis”, to determine the location of the discovery, which is the city of Dakhla, south of Dakhla. Morocco, the animal classification “sirene”.
Samir Zuhri tells Al Jazeera Net: It is a new genus and a new type of “sirenian” that provides new information about the history of the development of this group, as we also showed that this species had a clearly specialized anterior chewing surface (in the front of the lower jaw) that is not present in Other protozoans nor in contemporary dugongs, suggesting a different mode of feeding and possibly a particular environment.
According to Samir Zuhri, the fossils of these serines were discovered between 2013 and 2016 during several field missions, and they were prepared and restored in the fossil laboratory of the Department of Geology at the Faculty of Science in Ain El-Shaq, where the actual study began in fact since its discovery with a bibliographic search to collect the largest possible amount of Information about this group and to identify these fossil bones from an anatomical and taxonomic point of view.
The main challenge of the research team was the lack of collections of comparisons in Morocco with the already known serine fossils, and Zuhri notes that “this obstacle was overcome during the stay at the University of Michigan Museum of Paleontology, which houses one of the richest collections of fossils of representatives of this group. “.
A study of the evolution of these animals
According to the research team’s press release, Sirenians are the only current herbivorous marine mammals that have become exclusively aquatic, and Sirenians such as Cetacés: Baleines et Dauphins enjoy great interest in studying the evolution of these animals because they descend From terrestrial mammals that evolved into fully aquatic.
The Sirenins and Cetaceans transitioned from terrestrial to aquatic adaptations independently during the early to mid-Eocene (about 50-30 million years ago).
Sirenins are marine mammals that today include Dugong and Manatee that live in shallow tropical waters, especially in the Southern Hemisphere.
The current three species of dugongs “Manti” live along the coasts of the Atlantic Ocean and in the rivers of Latin America and West Africa, and the “Digong” dugongs live in the Indian and Pacific oceans. These current species are actually remnants of an extinct taxonomic order that culminated in the Miocene (24-53 million years ago), a period of warm global climate coinciding with large-scale shallow coastal habitats, the press release said.
Samir Zuhri explains that “one of the important differences between modern species of dugongs and manatees is that the latter no longer have the hind limbs that were present in the ancient forms, although protocyrine and cattle from the Eocene period can no longer use their limbs to walk on dry land.” .
The transition between the terrestrial environment and the aquatic environment during its evolutionary history imposed significant morphological and physiological modifications, and the discovery of fossil specimens makes it possible to trace the stages of this evolutionary process, and the study of Moroccan dugong fossils expands the knowledge regarding the “Protosirenidae”, the ancestral family of this group. Its members disappeared about 30 million years ago, according to the press release.
Zuhri adds: The Sirenins, such as whales, had gradually adapted to aquatic life, and within a few million years, they had fully adapted to life in water, and changes had occurred in anatomy, physiology, and others. Today, Sirenins are mammals. The only herbivorous marine extant and the only herbivorous mammals that became exclusively aquatic.”
Marine Vertebrate Study Project
It is worth noting that this scientific study is part of a project to study marine vertebrates from the Eocene era in the Sahara in southern Morocco, and their relationship to climatic changes at that time.
Moroccan researcher Samir Zuhri concludes his interview with Al Jazeera Net by saying, “This discovery, like many other discoveries that we have made in the region, encourages us to continue investigations, because all these excavations are useful to us, especially for reconstructing the history of ancient climate and palaeoecology at this time when It has experienced significant climate changes which can help us understand the current disturbances in the climate.”
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