Geoscience Reference
In-Depth Information
In the Early Triassic, the mammal-like reptiles still held sway, but more advanced types had replaced their
primitive cousins, the pelycosaurs, as the dominant land animals. These were the dicynodonts (“two dog
teeth”) and cynodonts (“dog teeth”). Bulky plant eaters, ranging from pigsize to rhino-size, dicynodonts have
been colorfully described by fossil trackway expert Paul Olsen of Columbia University as “Volkswagen
Beetles with tusks.” Many cynodonts were sabre-toothed carnivores that preyed on their dicynodont cousins.
Their dominance would be short-lived, however.
At the beginning of the Late Triassic, there was a proliferation of a spectacular reptile group called archo-
saurs, or “ruling reptiles.” They have best been described as “gatorlizards,” to use the term coined by Canadian
paleontologist Dale Russell. They included large aquatic reptiles called phytosaurs, which are considered the
original crocodiles and which looked very similar to the gavial crocodiles of India, with their long narrow
snouts ideally suited for snatching fish. The aetosaurs were a heavily armoured, reptilian version of the arma-
dillo with a piglike snout for grubbing for larvae and other invertebrates. The most formidable archosaurs were
the rauisuchids. These hulking quadrupeds could stand up on their hind legs and had a fearsome row of teeth
comparable to those of Tyrannosaurus, undoubtedly qualifying them as the tyrants of the Late Triassic.
PLINTHOGOM
