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Paleozoic Pre-Proto-Mammal Fossil Gallery
Animalia, Chordata, Vertebrata, Synapsida
(Kingdom, Phylum, Subphylum, Class)
Red text = needs information
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Pelycosaurs (Eupelycosauria) were a large group of early Synapsid tetrapods. They were carnivores and insectivores, and herbivores. They appear in the Late Carboniferous and became the dominant animals of the Early Permian. There were noticeable extinctions at the end of the Early Permian and at the end of the Middle Permian. Only a handful of species survived the Permian/Triassic Mass extinction. Two families survived into the Jurassic and one of those into the Early Cretaceous. From an early sphenacodontid the Therapsids evolve. They became the dominant animals of the Middle Permian and may have become warm blooded at this time. Therapsids did not have scales like reptiles, but they may not have had fur until the late Permian. One group of Therapsids were the Theriodontia ("beast tooth" or mammal-like teeth) that appear 265 mya in the Middle Permian. Bones in the head supporting the jaws shift. Some allow the jaw to open wider than the other reptiles and some become part of the ear for better hearing. These animals had larger teeth. They all had larger skulls, improved jaw muscles, and specialized teeth that were not continuously replaced. A survivor of the Permian/Triassic mass extinction were the Therodontia suborder Cynodontia ("dog teeth". These animals developed an upright gait. At first some grew to 6 feet long, but by the end of the Triassic they were all very small. |
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Pelycosauria (Eupelycosauria), Varanopseidae
(Order, Family)
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Varanops brevirostris Period: Vale formation, Clear Fork group, lower Permian Location: south of Abilene Texas Date found: February 14, 1998 Found By: Robert Burt Nickname: Junior Collection: Texas Memorial Museum at Austin, catalogue number TMM 43628 Collected& donated by: Jo Cox, Judie Ostlien, and Robert Burt Identified by: Bill May, Dr. Robert Reisz, Dr. Wann Langston, Dr. Stuart Sumida Prepared & described by: Dr. Robert Reisz & students, University of Toronto at Mississauga Photo by: Diane Scott, preparator, University of Toronto at Mississauga Size: ~ 60 cm long |
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Description: species name means "short snout". This is the only Varanops found outside the Cacops Beds of Archer County Texas. It is 30% larger than any other specimen. Varanops lived in the late Permian but disappeared before the Permian/Triassic mass extinction. This may have happened because of new forms of predators that appear at the end of the Permian. |
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Pelycosauria (Eupelycosauria), Sphenacodontidae
(Order, Family)
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Dimetrodon giganhomogenes Period: Vale formation, Clear Fork group, lower Permian Location: near Lawn Texas Year found: 1907 Collection: Texas Memorial Museum at Austin Size: ? mm long |
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Description: This is the "Lion of the Permian", the largest predator of the time. |
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Elongate vertebral spines formed the tall sail. This is like a series of ribs covered in skin that attached directly to the spine, no flexibility. Fossils show numerous healed bone fractures. The use of the sail may have been to regulate internal temperature or just for a mating display. Spine sails pop up occasionally in the fossil record. During the Permian two families of pelycosaurs had sails, the sphenacodontids (Dimetrodon, a carnivore) and edaphosaurids (Edaphosaurus, a herbivore). |
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