Lecture 14 Flashcards
What were the Ornithopoda called?
The “cattle of the cretaceous”
Where did the Ornithopoda live?
Spread all over the world from the arctic to antartica, lived in a range of habitats and climates
Were the ornithopoda abundant?
yes, evolved nearly 100 species
Why do we have such a great fossil record for the ornithopods?
Because they were common, widely distributed, and lived for a long time
What groups were the ornithpods in?
Ornithischians, Genasaurians, and Cerapodans
Why were the ornithopods the best chewers of all dinosaurs?
Because they had a strong depression of jaw joint below the tooth rows
What sizes were the ornithopods? did their size change as they developed? Did their locomotion change as they developed?
Early ornithopods were small and bipedal, later some members reached sized upto 17 m and became predominantly quadrapedal
What are three major derived groups of the ornithopoda?
The iguanodontia, the ankyllopollexia, and the hadrosauridae
How were the Ankylopollexians fingers and hands specialized?
The thumb was conical and pointed (for close-range defense or breaking open seeds and fruit)
the middle digits were tipped with hooves and fused so they could bear weight, the pinkie was flexible and could bend across the palm
What is another term for hadrosaurs?
Called the duckbilled dinos
What were the characters of the hadrosaurs in terms of chewing?
they had dental battery (which is rows of teeth constantly replaced) and they had modification of their feeding apparatus, they chewed by combining vertical movement of the lower jaw with the flaring movement of the maxilla to grind tough, low nutrition plant matter
What were the characters of the hadrosaurs in terms of their hands?
The thumb (digit 1) was lost, 3 fingers joined together in thickened pad to support weight during locomotion, there was no dexterity in the pinky (digit 5) and was smaller.
What was the main function of hadrosaurid hands?
to bear weight
while standing;
probably spent most
of their time on all
fours.
What are the two groups of the hadrosaurids? What’s the difference between them?
The hadrosaurines (solid crested)
The Lambeosaurines (hollow crested)
What were the specialized characteristics of the hadrosaurinae? What did they do? (4)
- Had small solid cranial crests or no crest at all
- Had accentuated nasal arch
- May have had inflatable flaps of skin covering nostrils and surrounding regions
- Used arch for head pushing during male-male combat
