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19 Cards in this Set
- Front
- Back
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What are two main clades of Saurischia?
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Sauropodomorpha
Theropoda Plus some early stem species that belong to neither group |
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What are synapomorphies (shared, derived characters) of the Saurischia?
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There are more than 12 synapomorphies but three main ones are:
Elongation of the rearward neck vertebrae- long necks Stronger articulations in back vertebrae Twisted and enlarged thumb |
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What are characteristics of the Sauropodomorpha?
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Extremely large (75,000kg=83 tons), long neck and tail, round body, quadrupedal
Up to 40m (131ft) long, 6m (20ft) tall at shoulder Tiny skull with very little brainpower Simple, peg-like teeth Nostrils toward top of head Pillar-like limbs with dense bones Most are incompletely preserved- not easily buried due to size Extremely long trachea- because of dead space, requires unidirectional breathing (like birds) Support of long neck using ligaments instead of muscular energy |
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What are the feeding characteristics of the Sauropodomorpha?
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Herbivore, simple teeth, small jaw muscles
Indiscriminant feeders Not great chewers Gastroliths Large gut with symbiotic bacteria |
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What are the locomotion characteristics of the Sauropodomorpha?
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Primitively bipedal, then became quadrupedal
Slow walkers (Prosauropods: 5km/h [3mph]; Sauropods: 20-30km/h [12-19mph]) Few prosauropod trackways in North America and Africa Many sauropod trackways in Americas, Europe, Asia, Africa |
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What is the social behavior of the Sauropodomorpha?
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Migratory long-distant movement
Gregariousness: "flocking" Defense via size and thumb claw |
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What are the growth and development characteristics of the Sauropodomorpha?
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Auca Mahuevo:
-Clusters of unhatched Sauropod eggs -Embryonic skeletons -Colonial nesting No Prosauropod eggs found yet High growth rate: 20yrs to maturity, 100yr lifespan Largest terrestrial life forms of all time! |
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What are the evolution characteristics of the Sauropodomorpha?
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Over a dozen synapomorphies
-Relatively small skull -Elongate, peg-like teeth -At least 10 neck vertebrae forming neck -Extra vertebrae in sacrum -Enormous thumb with claw |
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Prosauropoda is a common ancestor of?
What are two types of Prosauropoda? |
Common ancestor of Thecodontosaurus and Plateosaurus
Two types are Anchisauria and Plateosauria |
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What are characteristics of Anchisauria?
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Reduced face bones
Elongate forelimbs Straight femur Changes to pelvis and foot |
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What are characteristics of Plateosauria?
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Elongate cervical (neck) vertebrae
Reorganized sacrum Modified wrist |
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Sauropoda is a common ancestor of?
And what are the synapomorphies? |
Common ancestor of Blikanasaurus and Saltasaurus
Over a dozen synapomorphies -Changes in the cervical (neck) vertebrae -Increase in forelimb length -Changes in forefoot, hindlimb proportions: all related to larger size, graviportal movement |
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What are two types of Sauropoda?
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Eusauropoda
Neosauropoda |
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What are characteristics of Eusauropoda?
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Broadly rounded snout
Increase in the number of cervical (neck) vertebrae Modifications to forefoot, pelvis and hindlimb: more graviportal |
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What are characteristics of Neosauropoda?
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Cheek modifications
Changes in ankle Diplodocoidae -subrectangular snout -fully retracted external nares: nose on top of head Macronaria -Enlarge external nares: nose holes |
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What are potential problems with a very long neck?
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Dead space in the trachea
Extremely high blood pressure needed for high feeding Energy expense of constantly supporting head and neck |
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What traits are synapomorphies of Sauropodomorpha?
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Small skull
Elongate, peg-like teeth 10 or more vertebrae in neck Enormous thumb with claw |
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What trait is not a synapomorphie of Sauropodomorphia?
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Bipedal posture
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Definition is based on?
Diagnosis is based on? |
Ancestry
Synapomorphies |
