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19 Cards in this Set

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  • Back
What are two main clades of Saurischia?
Plus some early stem species that belong to neither group
What are synapomorphies (shared, derived characters) of the Saurischia?
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
What are characteristics of the Sauropodomorpha?
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
What are the feeding characteristics of the Sauropodomorpha?
Herbivore, simple teeth, small jaw muscles
Indiscriminant feeders
Not great chewers
Large gut with symbiotic bacteria
What are the locomotion characteristics of the Sauropodomorpha?
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
What is the social behavior of the Sauropodomorpha?
Migratory long-distant movement
Gregariousness: "flocking"
Defense via size and thumb claw
What are the growth and development characteristics of the Sauropodomorpha?
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!
What are the evolution characteristics of the Sauropodomorpha?
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
Prosauropoda is a common ancestor of?
What are two types of Prosauropoda?
Common ancestor of Thecodontosaurus and Plateosaurus
Two types are Anchisauria and Plateosauria
What are characteristics of Anchisauria?
Reduced face bones
Elongate forelimbs
Straight femur
Changes to pelvis and foot
What are characteristics of Plateosauria?
Elongate cervical (neck) vertebrae
Reorganized sacrum
Modified wrist
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
What are two types of Sauropoda?
What are characteristics of Eusauropoda?
Broadly rounded snout
Increase in the number of cervical (neck) vertebrae
Modifications to forefoot, pelvis and hindlimb: more graviportal
What are characteristics of Neosauropoda?
Cheek modifications
Changes in ankle
-subrectangular snout
-fully retracted external nares: nose on top of head
-Enlarge external nares: nose holes
What are potential problems with a very long neck?
Dead space in the trachea
Extremely high blood pressure needed for high feeding
Energy expense of constantly supporting head and neck
What traits are synapomorphies of Sauropodomorpha?
Small skull
Elongate, peg-like teeth
10 or more vertebrae in neck
Enormous thumb with claw
What trait is not a synapomorphie of Sauropodomorphia?
Bipedal posture
Definition is based on?
Diagnosis is based on?