What are Pelycosaurs?
Pelycosaurs (from the Greek pelyx meaning “bowl” and sauros meaning “lizard”) are an order of tetrapods that emerged during the Late Carboniferous, flourished during the Early Permian, then were replaced by their descendants, the therapsids, during the Late Permian. This primitive group was the dominant form of terrestrial life for about 40 million years, 3/5ths of the duration of dominance of mammals, and was among the first amniotes (non-amphibian tetrapods) to evolve. It is one of the most primitive groups of tetrapods, after basal tetrapods and early amphibians. Pelycosaurs ranged in size from a large rat to a wolf to bigger than an elephant. Being the dominant form of terrestrial life, they evolved to exploit numerous roles, including herbivores, insectivores, and carnivores. Some resembled robust lizards, others were more foreign, such as the iconic Dimetrodon grandis, an apex predator 3 1/2 meters (11 feet) in length, with huge vertebral extensions that created a large skin-cove
