plesiosauroid, adj.
/plee"see euh sawr'/, n.
any marine reptile of the extinct genus Plesiosaurus, from the Jurassic and Cretaceous periods, having a small head, a long neck, four paddlelike limbs, and a short tail.
[ < NL Plesiosaurus (1821), equiv. to Gk plesí(os) near, close to + -o- -O- + saûros -SAUR; orig. so named because of its conjectured nearness to modern reptiles, relative to the ichthyosaurs]

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      any of a group of long-necked marine reptiles (reptile) found as fossils from the Late Triassic Period into the Late Cretaceous Period (215 million to 80 million years ago). Plesiosaurs had a wide distribution in European seas and around the Pacific Ocean, including Australia, North America, and Asia. Some forms known from North America and elsewhere persisted until near the end of the Cretaceous Period (65 million years ago).

      Plesiosaurus, an early plesiosaur, was about 4.5 metres (15 feet) long, with a broad, flat body and a relatively short tail. It swam by flapping its fins in the water, much as sea lions (sea lion) do today, in a modified style of underwater “flight.” The nostrils were located far back on the head near the eyes. The neck was long and flexible, and the animal may have fed by swinging its head from side to side through schools of fish, capturing prey by using the long, sharp teeth present in the jaws.

      Early in their evolutionary history, the plesiosaurs split into two main lineages: the pliosaurs, in which the neck was short and the head elongated; and the plesiosaurids, in which the head remained relatively small and the neck assumed snakelike proportions and became very flexible. The late evolution of plesiosaurs was marked by a great increase in size. Kronosaurus, for example, was an Early Cretaceous pliosaur from Australia that grew to about 12 metres; the skull alone measured about 3.7 metres. Elasmosaurus, a plesiosaurid, had as many as 76 vertebrae in its neck alone and reached a length of about 13 metres, fully half of which consisted of the head and neck.

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Universalium. 2010.

Look at other dictionaries:

  • Plesiosaur — Ple si*o*saur, n. (Paleon.) One of the Plesiosauria. [1913 Webster] …   The Collaborative International Dictionary of English

  • plesiosàur — m geol. zool. fosilni reptil (Plesiosaurus), morska životinja vrlo male glave, duga vrata, dug do 13 m, živio u trijasu do krede; veslogmaz …   Veliki rječnik hrvatskoga jezika

  • plesiosaur — plesiosàur m DEFINICIJA geol. zool. fosilni reptil (Plesiosaurus), morska životinja vrlo male glave, duga vrata, duga do 13 m, živjela u trijasu do krede; veslogmaz ETIMOLOGIJA grč. plḗsios: bliz + saȗros: gušter …   Hrvatski jezični portal

  • plesiosaur — [plē′sē ə sôr΄] n. [< ModL Plesiosaurus < Gr plēsios, close, near, akin to pelos, near (prob. < IE base * pel , to push > FELT1, L pellere, to drive) + SAUR] any of an extinct group (order Sauropterygia) of large water reptiles of the …   English World dictionary

  • Plesiosaur — Taxobox name = Plesiosaur fossil range = Early Jurassic Late Cretaceous image caption = Plesiosaurus . regnum = Animalia phylum = Chordata classis = Sauropsida superordo = †Sauropterygia ordo = †Plesiosauria subordo = †Plesiosauroidea subordo… …   Wikipedia

  • plesiosaur — noun Etymology: ultimately from Greek plēsios close (akin to Greek pelas near) + sauros lizard Date: 1839 any of an order or suborder (Plesiosauria) of large carnivorous marine reptiles of the Mesozoic with dorsoventrally flattened bodies and… …   New Collegiate Dictionary

  • plesiosaur — noun Any of several extinct marine reptiles, of the order Plesiosauria, from the Jurassic and Cretaceous periods Look! cried Olson. Would you look at the giraffe comin up out o the bottom of the say? We looked in the direction he pointed and saw… …   Wiktionary

  • plesiosaur — n. extinct marine reptile of the Mesozoic era (having a small head, long flexible neck, four large paddlelike limbs and a short tail) …   English contemporary dictionary

  • plesiosaur — [ pli:sɪəsɔ:, pli:z ] noun a large fossil marine reptile of the Mesozoic era, with large paddle like limbs and a long flexible neck. Origin C19: from mod. L. Plesiosaurus, from Gk plēsios near (because closely related to the lizards) + sauros… …   English new terms dictionary

  • plesiosaur — ple·si·o·saur …   English syllables

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