Nothosaurs ruled the world’s oceans for 186 million years. Many theories of locomotion for nothosaurs have been proposed but no direct evidence of the method of locomotion has been discovered until now. Professor Qiyue Zhang from Chengdu Center of China Geological Survey, Professor Michael Benton from the University of Bristol, and Professor Shixue Hu from Chengdu Center of China Geological Survey are the first to discover physical proof of nothosaur locomotion. The research was published in the June 11, 2014, edition of the journal Nature Communications.
An ancient seabed in Yunnan, China provided the first direct physical evidence of how nothosaurs moved. The researchers found a series of slots arranged in ancient mud that indicate that the animals used their forelimbs to move on the ocean floor. The evidence includes animals that were between ten feet long and three feet long.
The paleontologists presume that the tracks were made by both the larger species of Nothosaurus and the smaller species Lariosaurus. The sizes of the imprints in the ancient ocean soil indicate that the animals were bottom feeders, The researchers explain that the evidence indicates that the ancient masters of the ocean primarily fed on animals extracted from the ocean floor by the long sharp beaks of the nothosaurs. Nothosaurs were a primarily predatory species that lived from 252 million years ago until 66 million years ago.
The discovery of actual tracks made by a variety of species of nothosaurs puts previous debate about the animal’s means of locomotion to rest. Nothosaurs were reptiles but are not considered to be dinosaurs. Nothosaurs arose to predominance about eight million years ago after the Permo-Triassic mass extinction. This is the first evidence that the species as a whole were bottom feeders that used their forelimbs as a means of locomotion for feeding. The animals were capable of swimming long distances according to other fossil records.