Lecture 10: Ceratopsian Dinos

Question 1

Ceratopsia: were they well studied? when did they first appear? Where?

Answer 1

Yes they were a well studied group, first appeard in late jurassic of Asia, mostly in cretaceous of North America and Asia, rare fragments from europe, great herds in alberta, Montana and wyoming.

Question 2

What are ceratopsia defined by?

Answer 2

Defined by the presence of a rostral bone forming the upper beak

Question 3

What are the main Genus’ of ceratopsia?

Answer 3

psittacosauridae, and the Neoceratopsia: basal neoceratopsians (including protoceratopsids and leptoceratopsids) and the Ceratopsidae

Question 4

Were psittacosaurus quadrupedal or bipedal?

Answer 4

Biped

Question 5

Were neoceratopsia quadrupedal or bipedal?

Answer 5

quadrupeds

Question 6

What are characteristic features of ceratopsia

Answer 6

Rostral bone: unique bone at tip of snout leading to a parrot like beak, a skull that is narrow at the beak and flaring, deep in the cheek region

Question 7

What are the features of their skull?

Answer 7

Frill is composed principally of paired parietal bones (on top of skull) strongly vaulted palate beneath the beak, separating nasal from oral cavity, folding of bones on tip of the head to from secondary skull roof, dental batteries

Question 8

Ceratopsid diagnostic characters

Answer 8

shape and number of horns, and shape and size of frills and hook on back of frill, long spikes extending from frill margin

Question 9

Pachyrostra

Answer 9

derived centrosaurines with thick bosses replacing horns

Question 10

Ceratopsian discovery

Answer 10

1870-1880s: cope and marsh. They found parts of pelvis, some teeth and vertebrae. Horn cores from Colorado misidentified by Marsh as belonging to a prehistoric bison, skull of triceratops in wyoming

Question 11

Finds in Alberta

Answer 11

1890’s-1910s: Lawrence Lambe (ottawa) centrosaurus, chasmosaurus, styracosaurus. Barnum Brown (new york) Anchiceratops, leptoceratops

Question 12

Finds in Asia

Answer 12

in 1923 ceratopsian dinosaurs discovered in Gobi desert, psittacosaurus, protoceratops

Question 13

Psittacosaurus

Answer 13

Means “parrot reptile”, parrot like beak with rostral nose, discovered in the Gobi in 1920s, hundreds of specimens, no skull frill, bipedal

Question 14

Ceratopsid diversity

Answer 14

one of the fastest growing dinosaur famillies, over a dozen new species recognized in the past 5 years ( first asian ceratopsid, oldest north american ceratopsids) lumpers vs. splitters

Question 15

How many complete and partial skulls of triceratops are there?

Answer 15

over 50

Question 16

Torosaurus?

Answer 16

One of the largest ceratopsians, 7-8 metric tons, Frill is made of thin bony struts and skin, not solid bone, some think this is the fully mature ontogenetic stage of triceratops, not a different genus

Question 17

Evolution

Answer 17

From small (1-2m) bipeds to large (5-10m) massive quadrupeds, only small and very basal ceratopsians in the late jurassic, basal neoceratopsians common in Asia through cretaceous, Ceratopsids first appear and are only found in late cretaceous, mostly in north america (rare exception in Asia)

Question 18

Abundance in North America

Answer 18

make up ~25% of late cretaceous Canadian fauna

Question 19

Feeding

Answer 19

herbivores, dense clusters of teeth in cheeks, teeth were replaced when worn, dental battery, sturdy coronoid process- a membrane bone on upper side of lower jaw to the back, lacking teeth. evidence for fleshy cheeks, good food processing within mouth. gastroliths found with psittacosaurus

Question 20

Chewing muscles

Answer 20

strong muscles for high efficiency mastication, attached through the upper temporal opening to base of the frill, attached to a sturdy large coronoid process on the manidble

Question 21

feeding position

Answer 21

Low browsing, no standing on hindlimbs, knocking down trees? diet: shrubby angiosperms, ferns, small conifers

Question 22

Locomotion

Answer 22

comparable to rhinoceros, usually slow but able to charge, tracks are uncommon, 2-4 km/hour, max running speed 30-35 km/hr

Question 23

Integument

Answer 23

quills or bristles on the tail of psittacosarus, scale impression from rest of body

Question 24

Social behavior

Answer 24

interspecific: among different species, intraspecific within the same species, Interspecific: role of horns, protection against predator

Question 25

Intraspecific behaviour

Answer 25

role in display, ritaulized combat (punctured wounds in frills and skulls) establishment of dominance, defense of territories, sexual selection

Question 26

What is the role of the frills?

Answer 26

Attachment for jaw muscles, protoceratops: frills increase with sexual maturity and larger in males, sexual selection

Question 27

Herd Living

Answer 27

Bonebeds indicate herd living, several thousand specimens, intraspecific behavior related to gregarious lifestyle

Question 28

Brain size

Answer 28

Small compared to body size, but larger than sauropods and stegosaurs, slow, uncomplicated lifestyle. keeping predators away with display of horns and frills