Lecture 23

Question 1

Marginocephalia Key evolutionary novelty

Answer 1

(‘margin-headed’)
-The presence of a thickened bony shelf (margin) at the back of the skull

Question 2

Ceratopsia Key evolutionary Novelties:

Answer 2

Frill on bony shelf at the back of their skull
Narrow beak with flaring jugals
rostral bone (upper part of the beak)

Question 3

The first ceratopsian appear:

Answer 3

In the Late Jurassoc of Asia and spread to North America during the Cretaceous

Question 4

A well-known primitive ceratopsian is:

Answer 4

Psittacosaurus.
This small biped is well known from Early cretaceous deposits of Mongolia China and Siberia

The name means “parrot lizard” has a small, rudimentary frill and large, pointy flaring jugals

Question 5

Neoceratopsians and it’s evolutionary novelties

Answer 5

Incredibly abundant in the Late cretaceoues of North america.

An extremely large head
broad and prominent frill
pointed and sharply keeled rostral bone
Limbs reflecting quadrupedalism

Question 6

Protoceratops

Answer 6

(“first horn face)
is abundant fossil in the sandstones of Mongolia (75-70)
Sexual dimorphism seen in the differing frills with the males being taller as well as a bigger bump on their nose

Question 7

Leptoceratops

Answer 7

Primitive neoceatopsians similiar to Protoceratops from North America.

Name means “little horned face”
found in rocks 66.8-66.0 in Alberta and Wyoming

Question 8

Ceratopsids have

Answer 8

Key evolutionary novelties

Very large skulls (1-2.8m skull length)
Large nasal openings
Prominent frills
a variety of horns
a dental battery

Question 9

Pachyrhinosaurus

Answer 9

“thick nosed lizard” is known from Alberta and Alaska (73.5-68.5 MA)
Centrosaurinae

Question 10

Triceratops

Answer 10

” Three-horned face” is one of the most abundant dinosaurse found as fossils in Hell Creek Fm

Question 11

Jack Horner and John Goodwin can be attributed to

Answer 11

The study of the ontogeny (growth) of Triceratops See slide 13

Question 12

Pachycephalosaurs

Answer 12

“Thick headed lizards”

a clade of bipedal, late Cretaceous marginocephalians with greatly thickened bones on the skull roof

Question 13

Also known from the same age range as the Triceratops, is the even larger:

Answer 13

Torosaurus “Perforated lizard”. Jack Horner believes it to be a mature adult Triceratops, but not all are in agreement

Question 14

Ontogomorphs

Answer 14

Jack Horner Museum of the Rockies) and Mark Goodwin (U of C Berkley) Argues that Dracorex and Stygimoloch are young Pachycephalosaurs - that the 3 dinosaurs are in fact ontogomorphs

Question 15

Pachycephalosaurs

Answer 15

Pachycephalosaurus
(“thick-headed lizard”)

Stygimoloch
(“Demon from the River Styx”)

Dracorex hogwartsia
(“dragon king of Hogwarts”)