Category Archives: Wikipedia

Description Dolphins are a widely distributed and diverse group of aquatic mammals. They are an informal grouping within the order Cetacea, excluding whalesand porpoises, so to zoologists the grouping is paraphyletic. The dolphins comprise the extant families Delphinidae (the oceanic dolphins),Platanistidae (the Indian river dolphins), Iniidae (the new world river dolphins), and Pontoporiidae (the brackish […]

Description Dimetrodon is an extinct genus of synapsid that lived during the Cisuralian (Early) Permian, around 295–272 million years ago (Ma). It is a member of the family Sphenacodontidae. The most prominent feature of Dimetrodonis the large neural spine sail on its back formed by elongated spines extending from the vertebrae. It walked on four […]