Lecture 14

Question 1

Maniraptorans

Answer 1

incredibly diverse,
highly derived
coelurosaurs.

Ossified sternal chest plate
semi-lunate wrist bone
Tibia longer than fibia
Feathered integument
Head larger than body

Question 2

Therizinosaurs

Answer 2

theriz = ‘to reap’ or ‘to
cut off’) have been found
in Early through Late
Cretaceous deposits in
Mongolia, China, and
western North America

Have gently curved claws

Question 3

Therizinosaurs evolutionary novelties

Answer 3

Novelties amongst this clade include:

Long necks

Wide pot-bellied torsos

A more upright posture

Relatively shorter tails

Leaf shaped teeth

Enormous claws

Question 4

Therizinosaur Beipiaosaurus inexpectatus

Answer 4

The Early Cretaceous therizinosaur Beipiaosaurus was relatively
small and less derived than later forms.

Had preserved feather integument of simple feathers
Shorter tail and pot-bellied torso

Beipiaosaurus remains come from the Yixian Formation of Liaoning Province.

Question 5

Therizinosauridae

Answer 5

The later, more derived
therizinosaurs
(therizinosauridae)
have an additional
evolutionary novelty
– the hallux (digit 1) moved
downward and became
a functional (weight-bearing) pedal digit.

See slide 9 photo

Question 6

Nothronychus

Answer 6

One therizinosaurid is known from
the Late Cretaceous (~92 Ma) of N.A.
Nothronychus (“slothful claw”) lived
in what is now Arizona & Utah. It
stood about 3.5 m (12 feet) to the top
of the head) with 30-cm long claws.

Question 7

The largest of the therizinosaurids is

Answer 7

Therizinosaurus (“scythe lizard”) –
from Late Cretaceous Mongolia (70 Ma)

Therizinosaurus had gently curved claws
almost 1 metre in length – the longest
known for any animal.

Question 8

Oviraptorosauria

Answer 8

Oviraptorosaurs (‘egg
thief lizards’) are known
from Asia and North
America (same as
therizinosaurs).
- Unique features:

Box like skulls
Short snouts
Deep/strong lower Jaws with very large mandibular fenestra
Few or no teeth
A short, thick tail

Question 9

Caudipteryx (Oviraptisauria)

Answer 9

In 1997 a small, basal
oviraptorosaur was identified
from the Yixian Formation of
Liaoning Province (early cretaceous 124.6 MA). The fossil had a spectacular clump of long feathers attached to the end of a
short tail. It was named
Caudipteryx (“tail feather”)

The last few vertebrae are fused in a way called a pygostyle

Gastroliths in the belly indicate a plant diet

Question 10

Oviraptorosaur Diversity

Answer 10

More derived
members include
the oviraptoridae (Asia) & Caenagnathidae (N.A. & Asia)

Early oviraptorosaurs such as
Caudipteryx is known from Asia.

Question 11

Oviraptorosaurs
name means _____

Answer 11

“Egg thief lizards”

It was originally thought that the nest the Oviraptosaur died beside belonged to the Protoceratops, and
that the oviraptorosaur had been killed as it tried to raid the nest, hence the name given to this new group of dinosaurs “egg thief lizards

However, the oviraptorosaur found
near the nest did not die attempting to steal the eggs, but instead died protecting its own egg nest!