Lecture 11

Question 1

What characters of the ornithischia are related to eating plants? (3)

Answer 1

The predentary bone at the front of the lower jaw helped in cropping veg, the ribs flare widely to give a large gut region, and the backward pointing pubis may have accommodated large gut region

Question 2

What kind of characteristics of ornithiscia lead to good chewing?

Answer 2

• Toothless, rough front tip
  of the snout.
• A jaw joint that is
  positioned below the level
  the tooth row
• Triangular-shaped cheek
  teeth with low crowns

Question 3

What diagnostic characters of the ornithscia are not related to food?

Answer 3

• the palpebral: a bony eyebrow
• the sacrum: part of the bone that attaches to hip and is made up of at least 5 vertebrae
• ossified tendons along back and tail (helps hold tail horizontally)

Question 4

Were the primitive ornothischians bipedal or quadrapedal?

Answer 4

bipedal

Question 5

What is the lesothosauras?

Answer 5

Is a small, leggy, Early Jurassic herbivore ornithsian It looked a lot like most primitive
dinosaurs, but with a jaw joint positioned below the tooth row.

Question 6

What does the ornithiscia get grouped into?

Answer 6

Genasauria

Question 7

What character makes us think that genasauria had well developed muscular cheeks?

Answer 7

The inset tooth row

Question 8

Further divisions within the genasauria are based on what?

Answer 8

How efficient chewing was in each group

Question 9

What are the further divisions of the genasauria?

Answer 9

thyreophora and the cerapoda (which includes the marginocephalia and the ornithopoda)

Question 10

What are the characters of thyreophorans?

Answer 10

Genasaurs with dermal armor-
bony plates embedded in the
skin-along the back surface of
the body- grow within the skin

Question 11

What are the characters of the cerapoda?

Answer 11

Genasaurs with a pronounced
diastema

Question 12

What does cerapoda mean?

Answer 12

cera= horn
pod= foot

Question 13

What are the characters of the marginocephalians?

Answer 13

A group united by having a shelf of bone extending over the back of the skull

Question 14

What does marginocephalians means?

Answer 14

Margin = margin; cephal = head

Question 15

What does ornithopoda mean?

Answer 15

Ornith = bird; pod = feet

Question 16

What are the characters of the ornithopoda?

Answer 16

Iguanodon, “duckbilled dinosaurs,” and other
excellent chewers

Question 17

What are the hadrosaurs?

Answer 17

Are a group of ornithischian dinosaurs called duckbilled dinos, cause they have broad duck like mouths

Question 18

Were duckbilled dinos actually duckbilled?

Answer 18

No, the soft tissue such as the rhampotheca extended down further, so the they had a downturned hooked bill

Question 19

What was the hooked bill used for?

Answer 19

• Gripping
• Ripping
• Breaking
  tough vegetation, rather than
  anything duck-like

Question 20

What further proof is there and duck billed dinos (hadrosaurs) weren’t actually duckbilled?

Answer 20

Data from coprolites which show that hadrosaurs were consuming tough material like conifer needles, twigs, and bark