Fearsome ancient otter
More than 6 million years ago, an otter the size of a wolf swam around the swamps of ancient southwestern China. At 110 lbs. (50 kilograms) the otter was a behemoth, about twice as heavy as the South American giant river otter (Pteronura brasiliensis), the largest otter living today. [Read the full story on the fearsome otter.]
The wolf-size otter lived in a swampy, shallow lake filled with aquatic animals, such as clams, as well as plants, according to other late Miocene-epoch fossils discovered nearby. The Miocene lasted from about 23 million to 5 million years ago.
Researchers found the otter in Zhaotong Basin, located in China's Yunnan province. Previously, researchers had discovered fossilized teeth of another large otter in Thailand's Mae Moh Basin that dates to the middle Miocene and one in China's Yushe Basin that dates to the Pliocene epoch (about 5 million to 2.5 million years ago).
Researchers went to Shuitangba quarry in search of something very different from an otter. In 2009, the field team discovered a skull of a juvenile hominoid skull known as Lufengpithecus, said study lead researcher Xiaoming Wang, a curator of vertebrate paleontology at the Natural History Museum of Los Angeles County in California.
"After that, we got funding to go back in 2010 because of the Lufengpithecus skull," Wang said. Instead, they found the wolf-size otter.
The ancient otter's skull is substantially larger than those of the modern-day South American giant river otter and the Eurasian otter.
A view of the skull from the right side and the top.
The wolf-size otter's upper teeth. Its large, rounded cheek teeth likely helped it crush large shellfish and freshwater mollusks, both of which are found in the Shuitangba quarry.
The otter's lower teeth.
The skull is like that of an otter, but the teeth are like those of a badger, the researchers said. Thus, they named it Siamogale melilutra. The species name honors both animals; in Latin, "meles" means badger, and "lutra" translates to otter, Wang said.
This isn't especially surprising, as the modern otter is in the family Mustelidae, which includes weasels, badgers, ferrets and martens.
Because the skull was flattened like a pancake, researchers did a computed tomography (CT) scan of the fossil. Then, study co-author Stuart White, a professor emeritus of maxillofacial radiology at the University of California, Los Angeles, digitally reconstructed the skull into a three-dimensional shape.
Each color in this digital scan represents an individual fragment.
Black and white
The final CT scan image, colored in gray. [Read the full story on the fearsome otter.]