cynodont

cynodont

▪ fossil reptile suborder
      (suborder or infraorder Cynodontia), mammallike reptiles of the order Therapsida (see therapsid) that existed from the Late Permian to the Early Jurassic Epoch (258 to 187 million years ago). Cynodont fossils have been found in China, South Africa, South America, and North America. (Examples in North America were not reported until 1989, from sites in Virginia, U.S.)

      The cynodont skull has many features anticipating that of a mammal. Notably, it has a secondary palate, as in a mammal, allowing it to simultaneously chew food and breathe, making for quicker digestion. (Most reptiles do not chew food but swallow it in large pieces, digesting slowly.) Thus cynodonts probably had a metabolic rate and large food requirement similar to mammals. They also had differentiated teeth, jaw bones, and jaw muscles suitable for chewing. Though the brain remained small, the braincase had an almost mammalian appearance, presaging the enlargement of the brain in mammalian descendants. Otherwise, the skeleton remained largely reptilian (the front and back limbs were appended on the sides, not underneath the body), signifying a sprawling posture and gait.

      The suborder Cynodontia contains, according to some classifications, five families—Procynosuchidae, Galesauridae, Tritylodontidae, Chiniquodontidae, and Trithelodontidae. The first mammals probably derived from small carnivorous chiniquodontids or trithelodonts sometime in the Middle Triassic Epoch (240 to 230 million years ago).

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Look at other dictionaries:

  • cynodont — n. any member of the Cynodontia, a group of small carnivorous reptiles. [WordNet 1.5] …   The Collaborative International Dictionary of English

  • Cynodont — Cynodonts Temporal range: Late Permian–present (Descendant taxon, Mammalia survives to present) …   Wikipedia

  • cynodont — noun Any of several small carnivorous reptiles closely related to the mammals …   Wiktionary

  • cynodont — 1. A canine tooth. 2. A tooth having one cusp or point. [G. kyon, dog, + odous (odont ), tooth] * * * cy·no·dont (siґno dont) [cyno + Gr. odous tooth] a canine tooth …   Medical dictionary

  • cynodont — n. canine tooth; tooth with one cusp; group of small meat eating reptiles …   English contemporary dictionary

  • cynodont — [ sʌɪnə(ʊ)dɒnt] noun a fossil carnivorous mammal like reptile of the late Permian and Triassic periods, with well developed specialized teeth. Origin C19: from Gk kuōn, kun dog + odous, odont tooth …   English new terms dictionary

  • cynodont — cyn·o·dont …   English syllables

  • cynodont — noun small carnivorous reptiles • Hypernyms: ↑therapsid, ↑protomammal • Member Holonyms: ↑Cynodontia, ↑division Cynodontia …   Useful english dictionary

  • Evolution of mammals — Restoration of Thrinaxodon, a member of the cynodont group, which includes the ancestors of mammals Further information: Evolutionary history of life The evolution of mammals within the synapsid lineage (sometimes called mammal like reptiles )… …   Wikipedia

  • Anexo:Terápsidos — Esta lista de terápsidos es un intento de crear un listado comprensible de todos los géneros incluidos en este grupo, excluye los mamíferos y los nombres vernáculos. La lista incluye todos los géneros aceptados por la comunidad científica, pero… …   Wikipedia Español

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