BACK TO DINOSAURS 1997 HOME PAGE

Lectures 19-20

Late Cretaceous - Mongolia, Judith River, Two Medicine, and Hell Creek

Late Cretaceous World

Late Cretaceous of Mongolia

Judith River Beds, Alberta

Two Medicine Formation. Montana

Dinosauria


Theropoda






1. three-toed foot

2. digits IV and V lost on hand

3. long arms

4. semilunate carpal

5. fused pelvis

6. large hole in lacrimal bone in skull

7. ?no unique derived characters?

8. giant, hook-like claw on digit II of pes

9. flight feathers

10. ?no unique derived characters?

11. proximal half of metatarsal of digit III pinched

12. teeth lost in front of mouth and very large claws on manus








	Coelurosauria

		Therizinosauria

			Therizinosaurus - Mongolia








1. proximal half of metatarsal of digit III pinched

2. enlarged brain and eyes and reduced teeth

3. metacarpals of nearly equal length

4. teeth with large denticles

5. highly reduced forelimbs and large size






		Arctometatarsalia

			Ornithomisauria

				Ornithomimus altus - Judith River

				Deinocheirus - Mongolia


			Troodontidae

				Saurornithoides - Mongolia

				Stenonychosaurus- Judith River


			Tyrannosauridae

				Tarbosaurus - Mongolia

				Albertosaurus - Judith River

1. three-toed foot
2. digits IV and V lost on hand
3. long arms
4. semilunate carpal
5. fused pelvis
6. large hole in lacrimal bone in skull
7. ?no unique derived characters?
8. giant, hook-like claw on digit II of pes
9. flight feathers
10. ?no unique derived characters?
11. proximal half of metatarsal of digit III pinched
12. teeth lost in front of mouth and very large claws on manus
13. skull deep, highly fenestrate, lacking teeth

		Ovaraptorids

			Oviraptor philoceratops


		Maniraptora

			Deinonychosauria

				Velociraptor - Mongolia

			Avialae

				Mononykus - Mongolia






1. semilunate carpal

2. giant, hook-like claw on digit II of pes

3. flight feathers

4. no shared derived characters?

5. tail becomes pygostyle

6. elongated digit III or hand

7. enlarged keeled sternum

8. no shared derived characters?

9. loss of teeth
10. spike-like manus








Ornithischia



	Genasauria

		Thyreophora

			Ankylosauria

				Nodosauridae

					Edmontonia - Judith River


				Ankylosauridae

					Euoplocephalus - Judith River







1. cheeks

2. armor

3. armor as plates or spines on back

4. "club" on tail

5. large armor plate on top of center of skull

6. armor as covering or small plates over back

7. armor as spines

8. armor as plates

9. uneven enamel on teeth

10. bony shelf on back of head
11. jaw joint below tooth rows









		Cerapoda

			Marginocephalia

				Pachycephalosauria

					Homalocephale - Mongolia

					Pachycephalosaurus - Judith River

					Stegoceras -  - Judith River


				Ceratopsia

					Psittacosauria
						Psittacosaurus mongoliensis - E. Cret., Mongolia
					Neoceratopsia

						Protoceratops andrewsi - Mongolia

						Centrosaurus - Judith River

						Monoclonius - Judith River

						Styracosaurus - Judith River


			Ornithopoda

				Hadrosauria

					Lambeosaurus

					Parasaurolophus

					Maiasaura






1. cheeks

2. armor

3. armor as plates covering back

4. armor as spikes or plates

5. uneven enamel

6. back part of skull makes shelf

7. rostral bone

8. frill

9. reduced hands

10. domed head

11. jaw joint below tooth row

12. elongate hands

13. prepubic process well developed

14. ridge on teeth

15. reduction in manus digits I and V (and large nares)

16. digit 1 of hand spike-like

Go to the Master Cladograms

BACK TO THE DINOSAURS AND THE HISTORY OF LIFE HOME PAGE