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Pedicellate Teeth
Pedicellate teeth are a tooth morphology today unique to modern amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ..., but also seen in a variety of extinct labyrinthodonts. Pedicellate teeth consist of a tooth crown and a base (both composed of dentine) separated by a layer of uncalcified dentine. Pedicellate teeth fossilize better than the rest of the body, these teeth are found in Stem amphibians. The synapomorphy of modern amphibian groups is proven through the shared fossil record. References Further reading * * External links * http://palaeo.gly.bris.ac.uk/Palaeofiles/Fossilgroups/Amphibia/characters.html Amphibian anatomy {{amphibian-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphibians
Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excluding the amniotes (tetrapods with an amniotic membrane, such as modern reptiles, birds and mammals). All extant taxon, extant (living) amphibians belong to the monophyletic subclass (biology), subclass Lissamphibia, with three living order (biology), orders: Anura (frogs and toads), Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater ecosystem, freshwater, wetland or terrestrial ecosystems (such as riparian woodland, fossorial and even arboreal habitats). Their biological life cycle, life cycle typically starts out as aquatic animal, aquatic larvae with gills known as tadpoles, but some species have devel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labyrinthodonts
"Labyrinthodontia" (Greek language, Greek, 'maze-toothed') is an informal grouping of Extinction, extinct predatory amphibians which were major components of ecosystems in the late Paleozoic and early Mesozoic eras (about 390 to 150 million years ago). Traditionally considered a Subclass (biology), subclass of the class Amphibia, modern classification systems recognize that labyrinthodonts are not a formal natural group (clade) exclusive of other tetrapods. Instead, they consistute an evolutionary grade (a paraphyletic group), ancestral to living tetrapods such as lissamphibians (modern amphibians) and amniotes (reptiles, mammals, and kin). "Labyrinthodont"-grade vertebrates evolved from Sarcopterygii, lobe-finned fishes in the Devonian, though a formal boundary between fish and amphibian is difficult to define at this point in time. "Labyrinthodont" generally refers to extinct four-limbed tetrapods with a large body size and a crocodile-like lifestyle. The name describes the patt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
