7 - Reptiles Flashcards
First amniotes maybe
Westlothiana (350mya), hard to tell because eggs fossilize badly
ancestors to reptiles
First reptile
Hylonomus 35my after westlothiana
Amniota
monophyletic lineage. reptiles birds and mammals
Extraembryonic membranes
protect embryo from desiccation
cushion embryo
promote gas transfer
store waste
Amniotic eggs of reptiles and birds
shells to protect embryo
albumen to cushion and provide moisture/nutrients to embryo
yolk supplies food to embryo
Reptile egg shell
leathery
Terrestrial adaptations other than amniotic eggs
impervious skin
horny nails
water conserving kidneys (Key, more efficient)
Enlarged lungs
mammals
most closely related to ancestral amniotes. branched off before lizards
reptiles and birds
reptilian lineage includes birds, dinos and other reptiles. Used to be considered further apart but now we know they are closely related. now avian and non-avian reptiles
mammal skulls
synapsida
all living reptile skulls
diapsida
Synapsid skull*
- mammals
- single temporal opening (fenestra) for jaw muscle attachment
Turtle skulls
diapsid + secondary loss of holes so looks like anapsid
Extinct taxa skulls
anapsid
anapsid skull
0 fenestra
Diapsid skull
- most reptiles and birds
- 2 temporal openings where jaw muscles attach to skull
Order testinudes
turtles
Order testinudes characteristics
bony shell (carapace - dorsal, plastron - ventral) limbs articulate internally to ribs keratinized beak instead of teeth
Turtle shell dorsal part
carapace
Turtle shell ventral part
plastron
Turtle reproduction
oviparous
Life history testinudes
- long life spans
- most mature after 7 years and live 14 or more after
- galapagos tortoises may live 100+ years
- no parental care of eggs so susceptible to predation
- very susceptible to extinction
What makes turtles vulnerable to extinctioni
- mature late and long lived
- large ocean ranges (can run into obstacles)
- nests on land (predation)
- used for food and medicine (eggs and adults) so killed by humans
Order crocodylia animals
- crocodiles
- alligators
- caimans
- gavials
Skull characteristics of crocodylia
- openings in front of eyes
- triangular eye orbits
- laterally compressed teeth
- secondary palate
Secondary palate
separates nasal and mouth passageways
allows breathing while eating or opening mouths underwater
Crocodilian reproduction
oviparous with parental care of hatchlings
Order sphenodontida
tuataras (almost extinct)
Order sphenodontida features
- akinetic jaw (lower attached to upper so strong bite)
- 2 rows of teeth on upper jaw
- single row of teeth on lower jaw
- oviparous
- new zealand
- first after mammalia
Order squamata
lizards and snakes
Order squamata skull
Kinetic skull:
- moveable quadrate bones and other skull modification
- increases skull flexibility
Order squamata 2 suborders
sauria - lizards
serpentes - snakes
Suborder sauria characteristics
- 2 pairs of legs usually
- upper and lower jaws unite anteriorly
- oviparous, ovoviviparous or viviparous
- includes legless amphisbaenia
Amphisbaenia
Legless squamates. Look like worms, some still have front legs
Reptiles most likely locations
warmer climates
Suborder serpentes characteristics
- legless
- skull adaptations for swallowing large prey
- mostly oviparous, some give birth to live young
Giant Galapagos tortoises
- used as food source on ships and rats got on island and ate eggs
- almost extinct
- Kept susceptible young in a conservation center and then let them go to save them
Galapagos iguanas
terrestrial but eat food from ocean so hunt in ocean then return to land
