New Species Of Whale Discovered In California Fossil Bed
Lawrence LeBlond for redOrbit.com – Your Universe Online
Fossil discoveries are nothing new. And finding new species is just as common. But when you find a fossil of an animal new to science, things start to get more interesting–especially when that discovery includes not one, but four new species from the same genus.
This is exactly what occurred in the Laguna Canyon outcrop, a fossil bed unearthed during a highway construction project in California in 2000. The site, which was excavated through 2005, revealed at least 30 cetacean skulls as well as an abundance of other marine creatures long lost to nature.
The cetacean fossils, which date back 17 to 19 million years (early Miocene epoch), are of four newly identified species of toothed baleen whales–a type of whale scientists believe had gone extinct around 5 million years ago.
The fossils were extensively studied by Meredith Rivin, a paleontologist at the John D. Cooper Archaeological and Paleontological Center (Cooper Center) in Fullerton, California, and her colleagues. She presented the findings at the annual meeting of the American Association for the Advancement of Science (AAAS) on Sunday (February 17).
Rivin, an expert in toothed baleen whale studies, explained there are two suborders of the cetacean order: Odontoceti (toothed whales), and Mysticeti (baleen whales). These two suborders share a common ancestor: the toothed baleen whale.
Mysticeti, which means mustache in Greek, refers to the baleen that hangs down from the jaw of this particular suborder of whale. But earliest baleen whales actually had teeth–a feature that is still seen in the fetuses of modern fin whales. However, in these whales, the teeth become absorbed before the enamel can form into actual teeth.
Rivin noted these new fossil finds are of the earliest known toothed whales to science. Three of the fossils belong to the genus Morawanocetus, which is familiar to paleontologists studying whale fossils in Japan, but had not been previously known in California. Together with the fourth fossil, which has been dubbed “Willy,” these new species represent the last known occurrence of aetiocetes, a family of mysticetes that coexisted with early baleen whales.
Rivin explained these new species are not ancestral to any living whale today, but rather are representatives of a transitional phase between toothed and toothless whales.
“Willy,” unlike the other three Morawanocetus fossils, is quite large, and could give Moby Dick a run for its money. While most modern baleen whales are giants in their own right, Willy is massive compared to the other three species. This is surprising, due to the fact experts believe gigantism in whales occurred relatively recently in the evolutionary scale–within the past 10 million years.
Nick Pyenson, a paleontologist with the Smithsonian Institution´s Museum of Natural History (MNH), said gigantism in the cetacean world has seemingly coincided with the onset of glaciation in the Northern Hemisphere during the Pliocene (5.3 to 2.5 million years ago).
Rivin also found the teeth of Willy were worn, suggesting (based on wear patterns and fossil remains in the deposit) the whale´s favorite food may have been sharks. She noted killer whales, who also enjoy a diet of shark, tend to have similar wear patterns in their teeth due to the roughness of shark skin.
While the new find is exciting, Pyenson said it still may not be clear what Rivin and her team actually have and what those fossils will reveal about the early evolution of baleen whales.
“I´ll be excited to see what they come up with,” Pyenson told Carolyn Gramiling at Wired.
Pyenson himself has made an astonishing whale discovery as well. In 2011, he was able to collect numerous 3D images of whale fossils at a site in Chile´s Atacama Desert. That fossil record, like the Laguna Canyon site, was also unearthed by a road construction project.
Rivin said her paper describing the fossils is still in preparation, and hopes to have more data on the three Morawanocetus fossils by the end of the year. She says it may take longer to describe “Willy” in greater detail. There´s still more work to do to free Willy from the rock, she punned.