Common ancestor of sharks and humans lived 440 million years ago
A team of scientists from Ireland and USA studied a 385-million-year-old shark fossils and revealed the evidence indicating that the common ancestor humans and sharks lived approximately 440 million years ago, says the study published in the Royal Society.
The researchers from the University of Chicago, University College Dublin and Cambridge University were studying a shark remains, discovered in Germany in 2001. The shark was toothless and on that reason gained the scientific name of Gladbachus adentatus.
The thorough study showed that the shark represented a transitional form between acanthodians and chondrichthyes. The findings allowed to estimate the time period during which humans and sharks shared a common ancestor – nearly 440 million years ago.
Moreover, the scientists defined that a shark lived approximately 385 million years ago, during a time period known as the Devonian, lasted from 416 million to 358 million years ago. During this period the first terrestrial vertebrates appeared.
The remains of a shark, consisted of three parts, were packed in resin. The resin coating preserved much of the endoskeleton and gave valuable tissue samples.
The preserved teeth, a cranium, cartilage and gill fragments were studied using computerized tomography. So, the complete picture of the creature’s look were drawn up. It has been found out that the body of the specimen looked like a sheet of scales, and that the bones in its head were very coarse.
The researchers have clarified the evolution process of this species. Some of the evolutionary lines were crossed, resulting in reflection of some characteristics inherent in modern sharks such as a long throat and multiple gill slits.
