Dinosaur Origins

Question 1

What are fenestrae?

Answer 1

Additional openings in the skull that don’t house additional sensory organs

Question 2

What are the three lineages of amniotes based off their skulls?

Answer 2

anapsids, synapsids, and diapsids

Question 3

What types of animals are synapsids?

Answer 3

Mammals and mammalian ancestors

Question 4

What is the well known synapsid from the permian period?

Answer 4

Dimetrodon

Question 5

What type of amniote are dinosaurs?

Answer 5

Diapsids

Question 6

What are the subgroups of Diapsids?

Answer 6

Lepidosauromorphs (no more additional fenestrae) and Archosauromorphs (Diapsids with an antorbital fenestra and the mandibular fenestra)

Question 7

Which animals are archosaurs?

Answer 7

Crocodilians, birds, dinosaurs and pterosaurs

Question 8

What group within archeosaurs do dinosaurs and pterosaurs belong to?

Answer 8

Avemetatarsalians

Question 9

What is the evolution that distinguishes avemetatarsalians?

Answer 9

Ankles that flex like a hinge rather than like a ball and socket, better suited for upright locomotion

Question 10

What is the group aside from avemetatarsalians?

Answer 10

pseudosuchians

Question 11

Which group of aminotes dominated the ecosystem during the permian period?

Answer 11

Synapsids, dimetrodon

Question 12

What were the major synapsid predators during the permian?

Answer 12

Gorgonopsids

Question 13

What were the major herbivores during the permian?

Answer 13

Dicynodonts

Question 14

What synapsid from the permian is the ancestor of current-day mammals?

Answer 14

Cynodonts

Question 15

What was the most devasting extinction event in history?

Answer 15

The end-permian extinction

Question 16

Is the cause of the end-permian extinction fully known?

Answer 16

No, we cant be certain

Question 17

Which lineage of amniotes took over the major parts of the ecosystem in the Triassic after the mass extinction?

Answer 17

Diapsids (Archosaurs)

Question 18

Which lineage of the archosaurs was most dominant during the Triassic?

Answer 18

pseudosuchians (crocodilians)

Question 19

What did the earliest dinosaurs-like archosaurs look like?

Answer 19

Small and Bipedal, no perforated acetabulum

Question 20

How old are the oldest dinosaur fossil bones?

Answer 20

228 million years old

Question 21

What allowed dinosaurs to dominate over pseudosuchians in the Jurassic?

Answer 21

end-triassic mass extinction that hit pseudosuchians hard

Question 22

What were the early carnivorous dinosaur?

Answer 22

Eorapter, Eodromaeus, Herrerasaurus, and Panphagia

Question 23

What was the early herbivorous dinosaur?

Answer 23

Pisanosaurus

Question 24

What was the largest early dinosaurs specimen?

Answer 24

Herrerasaurus

Question 25

What distinguishes dinosaurs from dinosaur-like archosaurs?

Answer 25

The perforated Actabelum

Question 26

What were the early dinosaur-like archosaurs called?

Answer 26

Dinosauromorphs