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26 Cards in this Set
- Front
- Back
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The first amniote radiation was seen in the _____________.
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early Permian
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The first amniote radiation was dominated by _________, once placed in the Pelycosauria group.
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Basal Synapsids
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Basal synapsids were all _______________, and had a sprawling gait.
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quadrupeds.
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The second amniote radiation was dominated by ___________.
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Therapsids.
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The Therapsid radiation was seen in the ____.
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late Permian -- early Triassic.
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What were the specializations of the Therapsids?
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Elaborated/differentiated teeth, enlarged infratemporal fenestra, reduced post-dentary mandible bones, forelimbs better developed than hindlimbs. (front-wheel drive)
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The boundary between the Paleozoic and Mesozoic is at ___________ ma.
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251.
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What species were the most affected from the mass extinction at the end of the Permian?
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marine invertebrates
therapsids and other tetrapods |
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What were the possible causes for the mass extinctions at the end of the Permian?
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Probably due in part to huge volcanic eruptions (largest in last half billion years), and possibly comet impact, with other factors adding to it
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This type of diapsid becomes more important during the Early Triassic...
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Archosaurs.
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These early Triassic diapsids may habe had specialized "belly breathing."
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archosaurs
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Third amniote radiation was seen in the ___________.
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middle-late triassic.
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The third amniote radiation of dominated by the ____________.
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Pseudosuchians
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Diagnosed by presence of the predentary bone (an extra bone joining the two anterior ends of the dentary, forming a beak) and five or more sacrals
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Ornithischia (bird-hips)
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Diagnosed by:
Long necks where posterior cervicals are longer than anterior cervicals Manus with an enlarged digit I ungual (thumb claw) Manual digit II is the longest in the hand |
Saurischia
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These Saurischians are Characterized by:
Enlarged nares An elongated neck Leaf-shaped teeth |
sauropods
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These saurischians are characterized by by extremely hollow limb bones.
Most retain the primitive condition of bladelike, serrated teeth, indicating they were carnivores All, from smallest to largest, were obligate bipeds |
Therapods
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Among the earliest plant eaters (Triassic), could be bipedal or quadrapedal, up to 11 meters long, massive or slender body, first digit of hang has a huge claw.
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prosauropods
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Describe Prosauropods.
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long neck, cheeks, jaw hing below line of upper tooth row, offset jaw, spatuate teeth, gastric stones.
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First major dinosaurs to go extinct.
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prosauropods
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Prosauropods went extinct in what period?
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early Jurassic.
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Quadrupedal herbivores, among the largest land animals of all time.
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Sauropods.
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Sauropod range =
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Early Jurassic - Late Cretaceous
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These sauropods are characterized by their long and lightly build bodies, long and slender skulls, peg-like teeth, and for having nostrils on top of skull
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diplodocids
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Robust sauropods with short and heavy skull, blunt snout, large spatulate teeth along entire length of jaw, large nostrils and a
12 neck vertebrae |
Camerosaurs
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This behemoth was a hundred feet long and weighed nearly one hundred tons and a member of a family of cretaceous period sauropods which are fittingly called "titanosaurs".
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Argentinosaurus
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