Definition of float in the AudioEnglish.org Dictionary. Meaning of float. What does float mean? Proper usage and pronunciation (in phonetic transcription) of the word float. Information about float in the AudioEnglish.org dictionary, synonyms and antonyms.
Mammals evolved from a group of mammal-like reptiles called the Synapsids, specifically the Therapsids, in the Triassic period, around 250 million years ago.
The non-mammalian members are described as mammal-like reptiles in classical systematics; they can also be called stem mammals or proto-mammals. Synapsids evolved from basal amniotes and are one of the two major groups of the later amniotes; the other is the sauropsids, a group that includes modern reptiles and birds. The distinctive temporal fenestra developed in the ancestral synapsid about 312 million years ago, during the Late Carboniferous period. Synapsids were the largest terrestrial vertebrates in the Permian period, 299 to 251 million years ago, although some of the larger pareiasaurs at the end of Permian could match them in size.