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20.01.2016 22:35 - Encyclopedia Largest prehistoric animals Vol.1 Vertebrates part 9 Basal Reptiliomorphs - Eupelycosaurs and Placodonts
Автор: valentint Категория: Забавление   
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1. Cotylorhynchus 2. Aerosaurus 3. Dimetrodon 4. Mesenosaurus 5. Edaphosaurus
The Eupelycosaurs first appear during the Early Pennsylvanian epoch (Archaeothyris, and perhaps an even earlier genus, Protoclepsydrops), and represent just one of the many stages in the acquiring of mammal-like characteristics, in contrast to their earlier amniote ancestors. The defining characteristics which separate these animals from the Caseasauria (also pelycosaurs) are based on details of proportion of certain bones of the skull. These include a long, narrow supratemporal bone  and a frontal bone with a wider connection to the upper margin of the orbit.
Many non-therapsid eupelycosaurs were the dominant land animals from the latest Carboniferous to the end of the Early Permian epoch. Ophiacodontids were common from their appearance in the late Carboniferous (Pennsylvanian) to the early Permian, but they became progressively smaller as the early Permian progressed. The edaphosaurids, along with the caseids, were the dominant herbivores in the early part of the Permian, ranging from the size of a pig to the size of a rhinoceros.
The most renowned edaphosaurid is Edaphosaurus, a large [10–12-foot-long (3.0–3.7 m)] herbivore which had a sail on its back, probably used for thermoregulation and mating. Sphenacodontids, a family of carnivorous eupelycosaurs, included the famous Dimetrodon, which is sometimes mistaken for a dinosaur, and was the largest predator of the period. Like Edaphosaurus, Dimetrodon also had a distinctive sail on its back, and it probably served the same purpose - regulating heat. The varanopid family passingly resembled today"s monitor lizards and may have had the same lifestyle.




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Автор: valentint
Категория: Политика
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