Cynognathus (Greek for "dog jaw"); pronounced sigh-NOG-nah-thus
Woodlands of South America, South Africa and Antarctica
Historical Period :
Middle Triassic (245-230 million years ago)
Size and Weight:
About 3 feet long and 10-15 pounds
Dog-like appearance; possible hair and warm-blooded metabolism
One of the most fascinating of all prehistoric creatures, Cynognathus may have been the most mammalian of all the so-called "mammal-like reptiles" (technically known as therapsids). Classified as a "cynodont," or dog-toothed, therapsid, Cynognathus was a fast, fierce predator, much like a smaller version of a modern wolf. Clearly it was successful in its evolutionary niche, because its remains have been found in middle Triassic sediments on three continents, Africa, South America and Antarctica.
The most interesting thing about Cynognathus is that it seems to have possessed many features normally associated with the first prehistoric mammals (which evolved from therapsids during the late Triassic period). Paleontologists believe Cynognathus sported a thick coat of hair, and may have given birth to live young (rather than laying eggs). Most startlingly, evidence points to Cynognathus having a warm-blooded, "mammalian" metabolism, quite unlike most of the cold-blooded reptiles of its day.