Lec 9 Reptilia

Question 1

When did Amniotes arose?

Answer 1

Carbonifeous

Question 2

What are the synapomorphies of Amniota?
(2 cranial, 1 post-cranial)

Answer 2

1. Frontal bone contacts orbits
2. Round occipital condyle
3. astragalus

Question 3

What are the 2 clades of Amniota?

Answer 3

Synapsida, Reptilia

Question 4

When did Amniota diversify?

Answer 4

Late Carboniferous

Question 5

What are the 2 key features of Cleidoic eggs

Answer 5

1. Semi-permeable shell: keep fluid in, allow gas exchange
2. Extra-embryonic membranes:
   chorion ( surround embryo and egg sac)
   amnion (surround embryo with H2O)
   allantois ( forms a sac for respiration and stores waste)

Question 6

3 Synapomorphies of Reptilia
(all cranial)

Answer 6

1. Maxilla separated from quadratojugal by jugal
2. No parasphenoid wings
3. 1 coronoid bone in lower jaw

Question 7

2 Clades of Reptilia

Answer 7

Parareptilia, Eureptilia

Question 8

2 Synapomorphies of Parareptilia
(1 cranial, 1 post-cranial)

Answer 8

1. No caniniform maxillary tooth
2. long and slender Femur

Question 9

What is the first aquatic amniote?

Answer 9

Mesosaurs

Question 10

What is the skull type of Parareptiles?

Answer 10

Anapsids, though some evolve temporal fenestrae

Question 11

What are the synapomorphies of Eureptilia?
(2 cranial, 1 post-cranial)

Answer 11

1. Small supratemporal bone
2. No postorbital-supratemporal contact
3. narrow iliac blade

Question 12

What are the 3 bones defining supratemporal fenestra?

Answer 12

parietal, postorbital, squamosal

Question 13

What are the 3 bones defining infratemporal fenestra?

Answer 13

postorbital, squamosal, jugal

Question 14

Synapomorphies of Diapsida
(2 cranial, 1 post-cranial)

Answer 14

1. upper & lower temporal fenestra (diapsid)
2. suborbital fenestra
3. ossified sternum

Question 15

Name an example of an early diapsid reptile

Answer 15

Petrolacosaurus

Question 16

Synapomorphies of Neodiapsida?
(3 all cranial)

Answer 16

1. lower temporal fenestra still present but open ventrally
2. No caniniform teeth
3. Subtemporal process of jugal slender

Question 17

2 clades of Diapsida

Answer 17

Archosauromorpha, Lepidosauromorph

Question 18

When did marine reptiles evolve?

Answer 18

Triassic after Permain-Triassic mass extinction

Question 19

6 Key features of Ichthyosauria
(2 cranial, 4 post-cranial)

Answer 19

1. elongate rostrum w/ naris positioned posteriorly
2. enlarged orbit with sclerotic plates
3. dorsal fin
4. flipper-like fore and hind limbs
5. reduced pelvic girdle
6. vertical, crescent-shaped tail
   (Hyperphalangy)

Question 20

Swimming style of Ichthyosaur

Answer 20

axial swimming, use axial undulations for propulsion

Question 21

Synapomorphies of Sauropterygia
(4 all cranial)

Answer 21

1. anterior teeth procumbent
2. no lacrimal
3. supratemporal fenestra larger than orbit
4. no lower temporal bar

Question 22

Which clade of Sauropterygia survived beyond Triassic

Answer 22

Plesiosauria

Question 23

What are 2 early sauropterygian clades and their characteristic?

Answer 23

Placodontians: enlarged flattened teeth
Pachypleurosaurs: long neck small skull

Question 24

2 key features of Sauropterygia: Plesiosaurs

Answer 24

large peddle-like limbs
massive limb girdles

Question 25

How do Plesiosaur swim?

Answer 25

Paraxial swimmers: use flippers to propel

Question 26

2 body morphotypes of Plesiosaur

Answer 26

Plesiosauromorph: long neck small skull
Pliosuromorph: short neck long massive skull