Lecture 20

Question 1

All ornithischians have these evolutionary novelties

Answer 1

• Toothless Predentary and a toothless premaxilla that make up the beak
• Ossified tendons (along dorsal vertebrae)
  -Ornithischian pelvis (pubis pointed to the back

Question 2

High EQ in theropods and ornithopods is associated with _____________

Answer 2

a high degree
of parental behavior.
 This includes large nesting colonies of the duck-bill (hadrosaurid)
dinosaur Maiasaura. Evidence reveals that not just hatchlings occupied the nest,
but young juveniles
stayed in the nest for
some time.

Question 3

Ornithopod evolutionary novelties
and characteristics include:

Answer 3

 “bird feet” 3 pedal digits
 no armour (no horns, spikes, etc.)
 horny beak (covered in thick keratin)
 no mandibular fenestra

Question 4

The most significant key
evolutionary novelty of
ornithopoda

Answer 4

Cranial kinesis.
(joints within the skull)

Upper jaw slides forward and outwards as the mouth closes which meant they didn’t have to chew their food.

Question 5

Ornithopod phylogeny

Answer 5

Ornithopoda
iguanodontians
hadrosaurids

Question 6

Iguanodontians have

Answer 6

long snouts and a widened,
toothless premaxillary.

Question 7

Iguanodon

Answer 7

Iguanodon (“iguana-tooth”) is an Early
Cretaceous iguanodontian. Recall it was one of
the first dinosaurs to be described scientifically
(1825).

Digit 1 spike
Digits 2,3 & 4 are bound together
Prehensile digit 5

Question 8

Hadrosaurs – ‘Cows of the Cretaceous’

Answer 8

 By the Late Cretaceous hadrosaurids largely replaced
iguanodontians.
 Hadrosaurs are abundant fossils found in the Hell Creek Fm (66-68MA)of
Montana and the Dakotas, outnumbered only by ceratopsians.

Question 9

Hadrosaurids

Answer 9

The evolutionary novelties /
characteristics for the hadrosaurids:
o no thumbs
o longer snouts
o broad beaks (‘duck bills’)
o dental batteries

 Paired with cranial kinesis, the
hadrosaurids became the most
efficient plant eaters of all time.

Question 10

A Complex Dental Battery

Answer 10

The batteries are not flat, in fact they are jagged.
For each tooth placement, different parts reach
the grinding surface at different times: dentine
(soft) and enamel (hard).

Question 11

Hadrosaurids - Lambeosaurines

Answer 11

Lambeosaurines are hadrosaurids with hollow crests that
connect with the nasal passages in either a U-shape or an S-shape.

North America 77-75 Ma
was home to a great
variety of
lambeosaurines.

Question 12

Lambeosaurine Crests

Answer 12

The inner ear and higher
level thinking areas of the brain are more
advanced, and thus it can be inferred that
the elaborate nasal cavity was likely used to
produce low bellowing sounds for
communication.

The crests provided visual display, but also
allowed for vocal display & communication

Question 13

Corythosaurus

Answer 13

(“Corinthian helmet lizard ”)

Question 14

 Lambeosaurus

Answer 14

(“Lambe’s lizard ”)

Question 15

Parasaurolophus

Answer 15

 Parasaurolophus (“near
crested lizard”) is the iconic
lambeosaurine with its
trombone-shaped crest.

Question 16

Hadrosaurids- Saurolophines

Answer 16

are hadrosaurids with solid crests or
fleshy combs.

Question 17

Edmontosaurus (“Edmonton lizard”)

Answer 17

Lived in North America
and was incredibly successful. The genus includes a number of
species that lived between 73 and 66 Ma. The giant herbivore is
12+ metres in length - comparable in size with T-rex!