lecture 15

Question 1

Mongolia’s Gobi Desert

Answer 1

was also a desert during the Late Cretaceous (85-70 Ma) but one with many oases surrounding waterways. Dramatic storms led to rapid burial in sand and hence a treasure trove of fossils.

Sandstorms blowing in would suffocate dinosaurs that were out in the open

Question 2

Oviraptorosaur Nests and Brooding*

Answer 2

An oviraptorosaur nest
is a raised mound that
surrounds an excavated
pit. Eggs were laid in
pairs over days and
weeks and sometimes
were a couple of layers
deep (up to 22 eggs in a
clutch) around nest perimeter

Brooding was done by the parents to both warm and protect the eggs by wrapping their long feathered forelimbs around the nest.

Question 3

Citipati

Answer 3

is an emu-sized
oviraptorosaur that lived
in Mongolia 75 Ma (Late cretaceous)

The thick mandible shows it’s from the oviraptoridae

Question 4

Anzu

Answer 4

Only North American oviraptorosaurs known from near-complete specimens.

Anzu was first identified in 2014 from 3 specimens collected in
the Hell Creek Formation (66 Ma). Anzu is nicknamed the
“Chicken from Hell”.

Question 5

Gigantoraptor

Answer 5

Gigantoraptor (“giant seizer”) is
known from just 1 partial,
disarticulated specimen from
Mongolia (~85 Ma).

~ 8m long and twice the size of a human

Question 6

Oviraptorosaurs were first discovered:

Answer 6

On a paleontology expedition to Mongolia in 1923 led by Roy Chapman Andrews

Question 7

Oviraptorosaur Diversity (Oviraptoridae &
Caenagnathidae)

Answer 7

Oviraptoridae have robust mandibles

Caenagnathidae: Slender mandibles with ridges and tooth-like bumps. Their mandible is also hollow and appears to be connected to the air-sac system