A Chinese giant otter has been discovered for the first time, says a new study published in the Journal of Systematic Palaeontology which draws a parallel between the creature and a wolf in terms of size. But, no, you cannot travel to see the wolf-otter anymore—it has been extinct for millions of years now.
Ancient Family of Otters
The ginormous extinct otter has been named Siamogale melilutra (S. melilutra). Its complete cranium was found in the Miocene Shuitangba site in Yunnan Province, China. It was as large as a modern wolf, with over twice the weight of existing otters, putting it in the list of the biggest otter species to be documented, according to the team of international researchers behind the study.
The S. melilutra comes from very ancient, extinct otters. The otter family to which it is ascribed, as per the analysis of the findings, represents one of the oldest lineages whose occurrence is traced back to at least 18 million years ago. This group was only known through fossilised isolated teeth spotted in Thailand from which little information was recovered, and so, the new discovery constitutes a huge step forward to understanding these creatures. The fossils found have provided data about a number of aspects of the animal: from its taxonomy to its evolution and functional morphology.
Working on the cranium, the researchers were able to generate a virtual reconstruction of what the giant otter possibly looked like. It was given the name “melilutra” because its dental features bore close resemblance with those of badgers (meles in Latin) and otters (lutra).
“While the cranium is incredibly complete, it was flattened during the fossilization process. The bones were so delicate that we could not physically restore the cranium. Instead, we CT-scanned the specimen and virtually reconstructed it in a computer,” says Dr. Denise Su, one of the authors.
Specialised Teeth to Eat Special Food
Comparable to a wolf in size, S. melilutra weighed nearly 50 kg. It wore a large, strong jaw, with rounded-cusped (bunodont) cheek teeth. These features indicate that the animal might have fed on large shellfish and mollusks; these food items are thought to have been abundant at Shuitangba back in the day, which used to be a swampy region. The artist’s representation of the two enormous otters puts them in a setting that looks like the environment in which they probably lived.
“From the vegetation and other animal groups found at Shuitangba, we know that it was a swampy, shallow lake with quite dense vegetation,” said Dr. Su.
Evolutionary History: Understanding Existing Otters
The bunodont teeth also puts the evolutionary history of otters in the spotlight.
“Multiple otter lineages have low-crowned bunodont teeth, leading us to ask the question if this was inherited from a common ancestor or if this was convergent evolution based on common dietary behaviors across different species,” says lead author Dr. Xiaoming Wang. “Our phylogenetic analysis suggests that bunodont dentition independently appeared at least three times over the evolutionary history of otters.”
Moreover, understanding the Siamogale has direct relevance to the existing species: we can better comprehend otter relationships as they occur today. Therefore, further digging into the findings will bring more answers, which, however, have not come without questions of their own.
“The discovery of the otter helps solve some questions about otter relationships, but has opened the door to new questions,” says Dr Wang.
Why Was the Wolf-Otter So Huge?
The researchers remain clueless as to the need for the large size of the otter. Nor do they know characteristics of its mobility: how did it brave the waters, and how did it move on land?
“Continued studies by our group will address these fundamental questions and give us a more complete picture of its paleobiology,” said Dr. Su.