Today, the Sahara seems to be one of the most lifeless regions of the world. But its fossils show it was once a huge fish filled with sea lanes and some of the largest sea snakes the planet has ever seen.
From 100 million to 50 million years ago, a large sea-dive covering up to 160 feet deep covered much of the West Africa leaves behind many marine fossils, including vertebrates, invertebrates, plants, and microbes. Many of them were surprisingly big. Due to the harsh geopolitical and physical climate, it is difficult to study this region. A group of scientists has therefore decided to assemble and assemble a large number of existing research results in this field. They paint a surprising picture of antiquity during a period that spanned 66 million years ago the event that put an end to big dinosaurs.
"K / Pg extinction is one of the largest mass extinction events," said study author Maureen O'Leary of Stony Brook University told Gizmodo. "We do not have a section in the rock record where the fossils are anchored at the species level, and we can observe these complicated changes on all continents." Data from the Trans-Saharan Seaway could fill some gaps as to how the extinction has affected an understaffed part of the world.
That Western Sahara was once a waterway has long been known to those who live there. The Tuareg have found remnants of marine life in the desert, O'Leary told Gizmodo, and the idea has been part of paleontological discourse for over a century. Between 50 and 100 million years ago, sea-level rise led to the creation of a waterway that probably linked the Gulf of Guinea to the Mediterranean. Scientists from the USA, Mali and Australia have analyzed fossils and sediments from three expeditions to the Sahara in Mali and published a bulletin detailing all previous knowledge about the region to illustrate what the ecosystem looked like.
] The shallow waters that covered the Sahara probably resembled other large seas that are today on continents such as the Caspian Sea, or the shallow warm waters around some Caribbean islands. On the shores of the sea route were probably mangrove forests, trees that are now found all over the world on tropical and subtropical shores. The fossils they found were strange and often very large, including a 5 foot catfish, 40 foot long sea snakes and other large fish, as well as relatives of today's crocodiles, sharks and elephants of their findings in the Bulletin of the American Museum of Natural History
] But why were the fish so big? There is a theory called island giantism that species on islands can become particularly large because they are protected from predators and have less competition for resources. Perhaps there is a similar version in aquatic environments – if the seaway is dehydrated, it may have left "water islands" on which similar evolutionary forces might have created large snakes and fish.
The region's fossil history offers another place to study K / Pg extinction. The effects of the event were not as dramatic as expected by O'Leary, she explained, with some of the species persisting both before and after extinction. However, the purpose of this paper was to lay the foundations for future researchers to build on to see the mass extinctions around the world. Much of the earlier research in the field was published in French, so many paleontologists may not be familiar with this region and its sediments, said O'Leary. But Mali is the site of ongoing conflicts that make scientists unsafe for field work.
Research shows how complex a corporate paleontology can be. Small-scale discoveries – one of the researchers found a fossil invertebrate animal that had buried itself in a previously fossilized pile, for example – as well as extensive planetary history beyond dirt and bone.
There is a lot to think about.