Reptile Radiation

reptile

a vertebrae amniote with scales, lungs, and typically lays shelled eggs on land

theropod dinosaurs

birds are derived from _____ _____, meaning they are technically reptiles in evolution

amniotes

vertebrates that produce an amniotic (where embryo develop on land instead of water) egg

synapsids

early amniotes with ONE temporal opening in the skull; ancestors of mammals

synapsid skull

1. legs move under body

2. specialized teeth

3. develop hair

synapsid evolution:
1.
2.
3.

pelycosaurs

early synapsids; lizard like with sprawling posture

therapsids

more advanced synapsids with upright posture and differentiated teeth

morganucodon

small, rat like early mammal

monotremes

egg laying mammals (ex: platypus); no nipples, lays eggs

placental mammals

develop young inside uterus with placenta for nutrient exchange

1. hair

2. mammary glands

3. endothermy

4. differentiated teeth

5. 3 middle ear bones

mammal traits:
1.
2.
3.
4.
5.

1. lays eggs

2. lacks nipples

monotreme traits:
1.
2.

1. live birth

2. placenta

placental traits:
1.
2.

sauropsids

reptiles plus bird lineage

anapsid skull

diapsid skull

none

living anapsid?

they evolved rapidly to fill niches left after Permian extinction

why were there many unique animals in triassic?

mosasaur

large marine predator; elongated body, paddle limbs, like a giant lizard

ichthyosaur

dolphin like; streamlined body, large eyes, fast swimmer

pterosaurs

flying reptiles (not dinosaurs)

1. long tails, small heads

2. short tails, large heads

two types of pterosaurs:
1. early →
2. later →