Smithsonian National Museum of Natural History Geologic Time The Story of a Changing Earth
Presented by the Department of Paleobiology.
The Permian
Contents
Overview
Terrestrial Animal Life and Evolution of Herbivores
Permian Terrestrial Floras
The Marine Realm and The End-Permian Extinction
, Climate, and the Formation of Pangea
Evidence
Late Permian brachiopods
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sample
Permian reef
Dimetrodon
Ophiacodon
Labidosaurus
Edaphosaur
Cotylorhynchus
Brachiopod
references and links
Foundational Concepts
Dating Methods
Earth Processes
Life Processes
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Terrestrial Animal Life and Evolution of Herbivores
The most important terrestrial herbivores in the Early Permian were the insects. They represented a mixture of holdovers from the earlier Pennsylvanian, such as the dragonfly-like palaeodictyopterans and various forms related to modern grasshoppers and cockroaches, as well as newly evolved forms such as beetles and scorpionflies that are the earliest known members of insect groups that undergo true metamorphosis. (Insects that metamorphose develop from egg to larva to pupa to adult, and generally make their living in a very different way in the larval and adult phases.) The advent of insects that could metamorphose had a profound effect on the ecology and evolution of insects, because immature life stages could use different resources than adults of the same species. Evidence for these new herbivores is seen in Permian plant fossils with new types of damage to leaves and seeds. Sedimentary rocks of Permian age also reveal fossil burrows made by the first insects to colonize quiet-water aquatic ecosystems.

The Permian terrestrial world hosted representatives of most major groups of vertebrates, although many appeared quite different from their modern relatives. A great diversity of amphibians lived on land and in nearby fresh water, including giant temnospondyl carnivores (Eryops), large herbivores (Diadectes), and many reptile-like forms (Seymouria and Limnoscelis). The two major groups of early amniotes, the synapsids (often called mammal-like reptiles) and true reptiles (diapsids and anapsids), had by now diversified into many different types. Some diapsids, such as the semiaquatic Youngina and the gliding Coelurosauravus, show very unusual adaptations. Armored pareiasaurs were some of the world’s first large vertebrate herbivores.

Early synapsids (pelycosaurs) were more abundant than early diapsids. Many of the first large herbivores were pelycosaurs, such as caseids and the sail-backed Edaphosaurus. Carnivorous forms were even more common, ranging from small varanopseids to the large Dimetrodon and Sphenacodon. Later in the Permian, more advanced forms evolved, such as the smaller and more mammal-like therapsids. Diverse therapsids are especially known from Russia and South Africa, including heavy-headed dinocephalians and gorgonopsians, rodent-like theriodonts, and cow-like herbivorous dicynodonts.

Although carnivorous animals radiated throughout the Permian, herbivory was probably the most noteworthy vertebrate adaptation. Herbivores require a suite of characteristics to effectively process plant material, which is often indigestible to vertebrates. These include varied tooth shapes that allow animals to crop and chew plants. These teeth often show well-developed occlusal (contact) surfaces that indicate food was being ground down in the mouth. In addition, vertebrate herbivores tend to be large, with spacious guts to process large amounts of plant materials. All of these features are seen in the vertebrate herbivores of the Permian.


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Overview | Terrestrial Animal Life and Evolution of Herbivores | Permian Terrestrial Floras
The Marine Realm and The End-Permian Extinction | Tectonics, Climate, and the Formation of Pangea



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