New species of prehistoric toothless dolphins discovered
Scientists have discovered a new species of toothless midget dwarf in the United States that lived about 28-30 million years ago.
The Inermorostrum xenops species lived during the same period as Coronodon havensteini, an ancient species of whale recently announced named, researchers said.
The skull of Inermorostrum was discovered by a diver on the Wando River in Charleston and presents the first clear evidence of aspiration power in marine mammals by ultrasound.
The researchers estimate that the dolphin is more than four feet long, smaller than its closest relatives, and significantly smaller than today’s dolphin peaks, which measure seven to twelve feet in length.
The dwarf dolphin had a small nose and completely missing teeth, said Robert W Boessenecker, professor of geology at the University of Charleston in the United States.
The name of the genus, xenops Inermorostrum means “snout of helplessness”, in reference to its state without teeth. The team believes that suckling dolphins mainly feed on fish, squids and other invertebrates with soft bodies of the seabed, similar to eating a walrus.
In addition, a series of deep canals and artery holes in the snout indicate the presence of a broad soft tissue, probably enlarged lips, and perhaps even a mustache, the researchers said.
“We studied the evolution of the length of the snout in cetaceans and found that during the Oligocene (there are 25-35 million years) and early Miocene periods (there are 20 to 25 million years), whales escape have rapidly developed extremely short muzzles and snouts Extremely long, adaptive radiation representative in behavioral feeding and specializations, “said Boessenecker.
“We also find that short snouts and long snouts have evolved so many times in different parts of the evolutionary tree – and that modern dolphins like dolphin peaks, which have a nose twice as long as wide, represent the optimum length because it allows capturing And suck the fish, “he added.
The discovery is an important step in understanding why the coast of South Carolina offers unique insights into the evolution of cetaceans, researchers.
“Coronodon, an Inermorostrum whale die and a baby dolphin, may well have fed the same prey,” said Jonathan Geisler, associate professor at the New York Institute of Technology in the USA.