Since mandibles do not appear to evolve as rapidly as the skull, the results show they are not reliable for identifying early dog fossils, Drake said.įour of 26 fossil mandibles from Ust’-Polui, which was occupied from 250 B.C. Other evidence also showed that these canids were domesticated: The remains were found within human dwellings, remains at both the Russian sites revealed butchery marks, indicating that they were eaten, and isotope analysis of canid and human remains from one of the sites – Ust’-Polui, in the Russian Arctic – showed canids and humans were both eating fish, and humans were feeding their canids. However, 3-D analysis of fossil records from four ancient sites, two from Russia and two from Alaska, found that most of those fossil mandibles could not be classified as either dog or wolf, even though features in canid skulls from the same sites as well as other data proved that the samples were dog remains. In a proof of principle, when analyzing the 3-D structures of mandibles of modern dogs, Drake and colleagues correctly classified 99.5 percent of the samples as being dog or wolf. Wolves have fairly straight mandibles while dog mandibles are curved, structural features that become evident in a 3-D scan. “Our study shows that when you measure modern dog mandibles and wolf mandibles using 3-D measurements you can distinguish them, and yet when we looked at these fossil mandibles, they don’t look like dogs or wolves.” Robert Losey, an anthropologist at the University of Alberta, Canada, is a senior co-author of the paper. “A lot of the fossil evidence for the date of dog domestication is based on morphological analysis of mandibles,” said Drake, the paper’s first author. 25 issue of the journal Scientific Reports. The researchers found that in the early stages of domestication, the skull changed shape but evolution of the mandible lagged behind and did not co-evolve with the skull. The other camp believes domestication occurred in the Neolithic age (17,000 to 7,000 years ago), when humans first established agriculture and civilizations.Ībby Grace Drake, a senior lecturer in the Department of Ecology and Evolutionary Biology, and her colleagues have been analyzing 3-D scans of ancient fossil canid mandibles to determine whether they belong to dogs or wolves. In the ongoing debate, one camp believes dogs were domesticated in the Paleolithic age (more than 17,000 years ago), when humans were hunter-gatherers. In an effort to settle the debate about the origin of dog domestication, a technique that uses 3-D scans of fossils is helping researchers determine the difference between dogs and wolves. This video shows how a canid mandible changes shape and curves during its transition from wolf to dog. Credit: Abby Grace Drake/Cornell University
0 Comments
Leave a Reply. |