Kategorie: News
Fossil bones show enormous dimensions
An extinct whale may be the heaviest animal that has ever lived on Earth. A research team was able to reconstruct the skeleton from the bones found and also calculate the body mass on the basis of the replica. In addition, the extraordinary find reveals new insights into the evolution of whales.
As the researchers report in the study, whales evolved into such large animals much earlier than previously thought. After examining the fossil whale skeleton, they assume that the forefathers of today's whales, porpoises and dolphins already lived completely in coastal waters about 39 million years ago and possessed enormous dimensions.
The researchers around Eli Amson from the State Museum of Natural History in Stuttgart estimate the weight of the animal in the scientific journal "Nature" at 85 to 340 tonnes. The species named "Perucetus colossus", ("the colossal whale from Peru"), is thus clearly a contender for the title of "heaviest animal of all time".
"The find changes the understanding of whale evolution," says Amson. The new study shows for the first time "that the gigantic body masses of whales were achieved 30 million years earlier than previously thought". Previously, the evolutionary transition to true gigantism in whales had been considered a relatively recent event, about 10 million years ago, he said.
Combination of gigantic size and bone weight
"Perucetus colossus combines gigantic size with extremely high bone weight," the 34-year-old researcher explains. "This whale drastically shifts the previously known upper limit of skeletal mass in mammals and aquatic vertebrates. It may also be the heaviest animal ever described."
Extra weight has helped marine-dwelling animals regulate their buoyancy over the course of evolution and keep themselves submerged, much like weight belts do for divers. The enormous weight of the "Perucetus colossus" can be explained by the accumulation of additional bone mass on the outside of the skeletal elements and by a higher bone density.
Vertebrae weighing more than 100 kilos
The fossil of the "Perucetus colossus" was discovered ten years ago in the desert on the southern coast of Peru. "Actually, the story of the discovery is really cool. Mario Urbina, one of the co-authors of the study, found something really strange on the coast 13 years ago, and it took us a long time to understand what it was and to prepare the fossil," Eli Amson tells us.
The exact location of the find was in the desert on the southern coast of Peru. Recovering the colossal skeleton was a major logistical challenge. Several excavations were required to collect the parts of the whale skeleton.
Each vertebra of the find weighs over 100 kilos, the ribs of the prehistoric whale are up to 1.4 metres long. At 5 to 8 tonnes, the 20-metre-long skeleton of the new species is said to be two to three times heavier than the 25-metre-long skeleton of a blue whale on display in the Hintze Hall of the Natural History Museum in London.
To estimate the weight of the specimen, the recovered and prepared bones were scanned and their volume determined. Core drilling was used to assess the internal bone structure. To reconstruct the body mass, the research team used the ratio of soft tissue to skeletal mass known in living marine mammals. "With the resulting estimates between 85 and 340 tonnes, the weight of the new species is in the order of magnitude of the blue whale or possibly even higher," reports the Stuttgart museum.