Only a metre in length and weighing less than 20 kilograms, Didelphodon had a rat-like appearance. The Didelphodon emerged in the Late Cretaceous from the same basic root as Placerias and cynodonts. Though these two mammal-like reptiles were extinct by the end of the Triassic, their descendants survived the cataclysm which curtailed the rule of the terrible lizards.
