An order of Paleozoic tetrapods that arose Carboniferous (Mississippian) (345 million years ago) and lasted until the Early Triassic (about 245 mya). The term anthracosaurs (meaning “coal reptiles”) encompasses a range of genera that may not all be close relatives; rather, they form a stem group (members of the lineage leading to amniotes, but not amniotes themselves) possibly related to amniotes (reptiles, birds, and mammals). They share a number of features, such as the pattern of skull roof bones and vertebral construction, that distinguish them from temnospondyls, a larger group of Paleozoic tetrapods that are more closely related to modern amphibians. Anthracosaurs also share a number of features that may be primitive for tetrapods, including a “skull table” unit that is only loosely attached to the cheek, and a palate in which bones almost meet along the midline.