(2011) argued that the procolophoniddominated Late Triassic tetrapod assemblages from the Newark Supergroup existed under semi-arid climatic conditions, whereas more or less coeval communities dominated by traversodontid cynodonts
from Virginia and North Carolina appear to have been restricted to a narrow equatorial zone with more humid conditions.
Co-author Dr Jennifer Botha-Brink of the National Museum in Bloemfontein, South Africa said that during the Triassic, the cynodonts
split into two groups, the cynognathians and the probainognathians.
Rowe began scanning skulls from the reptilian ancestors of mammals, cat-size creatures called cynodonts
Studying a transect of Pangaea stretching from about three degrees south to 26 degrees north (a long swath in the center of the continent covering tropical and semiarid temperate zones), a team of scientists led by Jessica Whiteside at Brown University has determined that reptiles, represented by a species called procolophonids, lived in one area, while mammals, represented by a precursor species called traversodont cynodonts
, lived in another.
, extinct mamma-like reptiles that gave rise to true mammals, bore just such a trough.
The process of development can be traced by following the evolution of pelycosaurs (animals with spiked sails on their backs that resembled large Komodo dragons) to cynodonts
, whose jaws and related muscular features were much closer to those of mammals.
Smith & Kitching (1997) reported a bed of pedogenic nodule conglomerate rich in terrestrial vertebrate remains, including skulls and partial skeletons of cynodonts
, in floodplain deposits of Lower Jurassic age in South Africa, which they likewise attributed to a regional base level drop.
Several newly prepared fossil specimens are described, which suggest that respiratory turbinals did, in fact, occur among therocephalians and cynodonts
, two groups of advanced therapsids.
Although two different groups of very mammal-like non-mammalian cynodonts
are known from the McCoy Brook Formation, no diagnostic skeletal remains of mammaliaforms have yet been recorded from this unit.
Among the remains, the researchers identified seven previously unknown species, including four cynodonts
, which were the earliest mammal-like reptiles, and one rynchosaur, a parrot-beaked reptile of a group that disappeared shortly after dinosaurs emerged.
In July 1965, Bob Carroll, while collecting with Don, found a fragment of a very large dentary (YPM VPPU 019190) at Burntcoat, which proved to be the first record of a traversodont cynodont
from North America.