A sail-backed Dimetrodon from Earth's Permian period of time.

AGGRESSION • AMNIOTE • AMPHIBIA • AMPHIBIAN • AMPHIBIOUS • ANIMAL BODY • ANIMAL MOUTH • ANIMAL SCALE • ANIMAL TEETH • 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 • GEOGRAFIA • GEOGRAPHY • GEOLOGIA • GEOLOGY • GRAZING • GROWL • HISSING • HORIZONTAL • ILLUSTRATION • ILLUSTRATIONS • ILUSTRATION • LANDSCAPE • LANDSCAPES • LARGE • LATERAL VIEW • MOUTH OPEN • NATURAL HISTORY • NATURAL SCIENCES • NATURE STUDY • NATURE • NO PEOPLE • ONE ANIMAL • OPEN MOUTH • OPEN-MOUTHED • OUTDOOR • OUTDOORS • OUTSIDE • PALAEONTOLOGY • PALAEOZOOLOGY • PALEOBIOLOGY • PALEOGEOGRAPHY • PALEONTOLOGY • PALEOZOIC ERA • PALEOZOOLOGY • PAST • PELYCOSAUR • PERMIAN • PREDATOR • PREHISTORIC ERA • PRIMITIVE • REPTIL • REPTILE • REPTILES • RIVER • ROAMING • ROARING • SCIENCE • SCIENCE: EVOLUTION • SHORE • SHORELINE • SIDE VIEW • SNARLING • SPECIES • SPHENACODONTIDAE • SPINE • STREAM • SYNAPSID • TERRAIN • TOUGHNESS • VERTEBRA • VERTEBRATE • WATER • WILDERNESS • WILDLIFE • WITHOUT PEOPLE • ZOOLOGY