Extinct reptiles

Question 1

Basic anatomical and reproductive differences

Answer 1

Skin covered by scales
Eggs are apergaminate (soft) or calcerous (hard) shells.
Some groups can develop embryo retention and viviparity
Larval stages do not exist

Question 2

Reptiles

Answer 2

All members of the amniote clade that includes turtles, lizards, crocs

Question 3

Diapsids

Answer 3

Reptiles with two skull openings behind orbit: the lizard-croc clade

Question 4

Neodiaspid

Answer 4

Diaspid clade that includes youniniformes + Sauria

Question 5

Lepidosaurs

Answer 5

Tuatara and kin (rhynchocephalians) and squamates
Mostly small diaspids with flexible skulls, in evolution appearance of different kinetic zones in skull.

Question 6

Squamates

Answer 6

Snakes, lizards, amphisbaenians
Over 7500 species
Lizards paraphyletic to amphisbaenians and snakes

Question 7

Archosauromorphs

Answer 7

Mostly terrestrial triassic animals, include small, lizard-like predators and omnivores, long-necked amphibious forms, specialised herbivs

Question 8

Archosaurs

Answer 8

Crocs and kin, pterosaurs, dinosaurs and kin

Question 9

Diapsid skull

Answer 9

Evolved from an anapsid ancestor.
Diapsid skull present in lizards, snakes, crocs and birds
Large eye, flat upper jaw.

Question 10

Turtles

Answer 10

Have an anapsid skull so are outside of Diapsida
However molecular data places them deep within Diapsida, so they have evolved this anapsid skull from a diaspid one

Question 11

Evolution of locomotion in water

Answer 11

Discontinuous locomotion: propulsion generated during the power stroke.
Continuous: Axial by body/tail, can be axial undulatory swimmers (wave like sweeps) or axial oscillatory (swivelling of propulsive structure)
Paraxial locomotion uses lift or drag limbs

Question 12

Salt and sea water

Answer 12

Marine mammals void unwanted salt via efficient kidneys that produce concentrated urine.
Reptiles don’t have such efficient kidneys instead they use skull glands

Question 13

Sauropterygians

Answer 13

Major calde of mesozoic marine reptiles.
Key characters: euryapsid condition, retracted external nostrils

Question 14

Placodonts

Answer 14

Triassic sauropterygians from EU, Middle E and Chinga.
Evolved turtle like armour of interlocking scutes

Question 15

Pachypleurosaurs

Answer 15

Small amphibious triassic sauropterygians.
Some suction feeding features.
Embryos show viviparity present already

Question 16

Plesiosaurs

Answer 16

Carnivorous mesozoic marine reptiles
200-65 mil years ago
Plesiosaurs are derived sauropterygians

Question 17

Plesiosaur Characteristics

Answer 17

Wing-like flippers, short tail possibly with vertical fin
Modified diapsid skull.
100s of tiny teeth, filter feeding?

Question 18

Pistosaurs

Answer 18

Ancestors of plesiosaurs
Resemble plesiosaurs in having retracted nostrils, simplified humerus shape.
Enlarged wing shaped hands suggest paraxial locomotion

Question 19

Icthyosaurs

Answer 19

Carnivorous mesozoic marine reptiles
Approx 200-90 million years ago
Exact origin unkwon
Teeth set in grooves
Increasingly fish like through time
Huge eyes
Live birth

Question 20

Mesozoic marine reptiles within reptilia

Answer 20

Difficult as have strongly modified morphology
Seems are lineages are within Neodiapsida.

Question 21

Cretacous lizards to the sea

Answer 21

Several lineages of anguimorphy lizards took to seas.
Long bodied shallow water foragers.

Question 22

Mosasaurs

Answer 22

Large to gigantic aquatic anguimorphs.
Flexible lower jaw.
Longer snout, retracted nostrils, longer and wider paddle like limbs and tail