Mammal-like reptiles, page 2

the human dinos were called Australopithecines, or the Evolutionary Humim. Posted by Isis

KKing123 is correct, Australopithecines were early hominids. The first proto human found was found by Richard Leakey, and he labeled her Australopithicus Afarensis (Southern Man, located in the Afar region of Tanzania). This skeleton later became known as "Lucy" as it was determined to be an adolescent female.

Australopithecines were essentially highly developed and evolved apes. Although Lucy was not fully bipedal, she was found to be capable of bipedal movement for extended periods, with modern apes only able to do so for short distances.

Lucy was estimated to have lived about 5 million years ago, which is far after the end of the dinosaurs, who died out at the end of the Cretacious period about 65 million years ago.

The Dimetrodon you mentioned is a very early dinosaur, dating back to around 150-200 million years ago, into the Triassic period. This dinosaur *was* cold blooded, as evidenced by the fin back. Because cold blooded animals cannot move or do anything very energetic until thier internal temperature reaches a certain temperature, and due to the relatively large body mass of Dimetrodon, it evolved that fin back. It is estimated that the fin contained a large network of blood vessels, and when its temp was low, it would sit 90 degrees to the sun, presenting the max surface area to sunlight, heating its blood. If it began to overheat, it would turn face on to the sun, and allow heat to radiate out into the air.