Sail-backed Dimetrodons, alive during Earth's Permian period of time.

AMNIOTE • AMPHIBIA • AMPHIBIAN • AMPHIBIOUS • ANIMAL BODY • ANIMAL SCALE • ANIMAL THEMES • ANIMAL • ANIMALS IN THE WILD • APEX PREDATOR • ARTWORK • BACKBONE • CARNIVORE • COLOR IMAGE • COLOUR IMAGE • CREATURE • DAY • DIGITALLY GENERATED IMAGE • DIMETRODON • DINOSAUR • DINOSAURS • ENVIRONMENT • EVOLUTION • EXTINCT • FIERCE • FULL LENGTH • FULL-LENGTH • GEOGRAPHY • GEOLOGIA • GEOLOGY • GRAZING • HORIZONTAL • ILLUSTRATION • ILLUSTRATIONS • LANDSCAPE • LANDSCAPES • LARGE • LATERAL VIEW • NATURAL HISTORY • NATURAL SCIENCES • NATURE STUDY • NATURE • NO PEOPLE • OUTDOOR • OUTDOORS • OUTSIDE • PALAEONTOLOGY • PALAEOZOOLOGY • PALEOBIOLOGY • PALEOGEOGRAPHY • PALEONTOLOGY • PALEOZOIC ERA • PALEOZOOLOGY • PAST • PELYCOSAUR • PERMIAN • PREDATOR • PREHISTORIC ERA • PRIMITIVE • REPTIL • REPTILE • REPTILES • ROAMING • SCIENCE • SCIENCE: EVOLUTION • SIDE VIEW • SPECIES • SPHENACODONTIDAE • SPINE • SYNAPSID • TERRAIN • TOUGHNESS • TWO ANIMALS • VERTEBRA • VERTEBRATE • WILDERNESS • WILDLIFE • WITHOUT PEOPLE • ZOOLOGY