For over 130,000,000 years, mammals rived side by side with the now extinct large dinosaurs, and some early mammal relatives even are mistaken for dinosaurs, such as the sail-back synapsid
Dimetrodon, a fossil featured in this section.
John combined his assessment of the age of the Pictou Group in the Malpeque Bay area with Doffs information to conclude that the tracks represented a latest Pennsylvanian to earliest Permian occurrence of the ichnogenera Notalacerta and Gilmoreichnus, most likely made by a basal reptile and a basal synapsid
Washington, July 29 (ANI): A team of paleontologists from the Field Museum, US, has described the first vertebrate to live in trees as the small plant-eating synapsid
, which lived in the Late Paleozoic, 260 million years ago.
(therapsids) are represented only by the large traversodontid cynodont Arctotraversodon plemmyridon (Hopson 1984; Sues et al.
When a group of reptiles called the synapsids
branched off from the main reptile line to become the precursors of mammals, the jaw again underwent changes.
During the Middle Triassic, however, synapsids
appear to be generally uncommon in tropical to subtropical Pangaean strata (as is the case for the Economy Member of the Wolfville Formation) while they are abundant at higher latitudes in both hemispheres (Sues and Fraser 2010).