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Part 6 - Class Amphibia and tetrapod origins
Class Amphibia (sensu stricto)
3 living orders
Class Amphibia also called Lissamphibia
All sorts of “amphibians” in the fossil record
lobe-fin fish
†early tetrapods: labyrinthodonts, ichthyostegans, “fish-o-pods”
Lepospondyli, †Anthracosaurs
Amnoita
Temnospondyli
Lissamphibia = Class Amphibia (s.s.)
† various dead ends
† various dead ends
† various dead ends
aquatic
terrestrial
fish
tetrapod
non-Amniote, non-amphibian tetrapods
non-Amniote, non-amphibian tetrapods
Often called “amphibians”
Class Amphibia
non-Amniote, non-amphibian tetrapods
Tetrapod Origins
Ray Troll
“Fishes”
Internal choanae (nares)
Rhipidistian “fish”
Eusthenopteron
Eusthenopteron
Rhipidistian “fishes”
Probably ‘terrestrial’ only in an emergency
“fish-o-pods”
Tiktaalik
“Fish-o-pods”
Tiktaalik
“fishes”
“fishopod”
tetrapods
1st terrestrial tetrapods
“Fish” Tetrapod
?
Limbs with digits
strengthened limb girdles
† Acanthostega
Early tetrapod trackway
1st Terrestrial tetrapods – Ichthyostegans, Labyrinthodonts
Labyrintodonts
Ichthyostega
Labyrintodonts
1st terrestrial tetrapods
A divergence
Lepospondyls
Terminospondyls
on to amniotes
on to amphibians
Lepospondyls and Antracosaurs
Lepospondyls and Antracosaurs
Anthracosaurs
trending more terrestrial
Lepospondyls and Antracosaurs
On to the amniotes ….
One hypothesis
Early amniotes
Anthracosaur – anamniote
But first the amphibians
Ray Troll
Devonian 416-360 mya
Carboniferous 360-300 mya
Temnospondyli
Terminospondylson our way to amphibians (sensu stricto)
EryopsTemnospondyli
Lissamphibia Class Amphibia (sensu stricto)
Class Amphibia (sensu stricto)
360-300 mya
Originated and diversified the Carboniferous
Class Amphibia
Problems with Terrestrial Living
Problems with Terrestrial Living
Solutions
Solutions
Senses
Olfaction and hearing
Hearing
Solutions
Senses
SolutionsRespiration
lungs and skin
Solutions
Circulation
Single pump / single circuit system
FishesCirculation
Tetrapods - primitive
Separate respiratory and systemic circuits
lungs
body
Circulation
Fishes AmphibiansCirculation
Solutions
Circulation
to skinto skin
lunglung
Amphibian heart
Wastes
Skeletal and muscle innovations
Amphibians still tied to water
lobe-fin fish
†early tetrapods: labyrinthodonts, ichthyostegans, “fish-o-pods”
Lepospondyli, †Anthracosaurs
Amnoita
Temnospondyli
Lissamphibia = Class Amphibia (s.s.)
† various dead ends
† various dead ends
† various dead ends
aquatic
terrestrial
fish
tetrapod
Class AmphibiaLiving Diversity
3 orders
Order Gymnophiona (aka Apoda)
caecilians
Order Caudata (aka Urodela)
Salamanders
Japanese giant salamander (Andrias japonicus)
Plethodontidae
Salamander Eggs
Aneides aeneus – green salamander
Gill bearing Salamander larvae
Neoteny
Paedomorphosis
Amphiuma
Siren
Cryptobranchus
Plethodontidae
our family has no lungs
Order Anura
Frogs and toads
Triassic Frogs
Frog and Toad
Rana
Leopard frogs
Hyla
Tree frogs
Toads
Bufo
Size range
Burrowing and Hibernating
Frog Calls
Frog Calls
Amplexus
Frog Eggs
Tadpoles
Metamorphosis
Feeding niches
Rana catesbeiana
Bull Frog
Bull Frog
Bull Frog
Some native Arizona leopard frogs
Protected Arizona snake
MEXICAN GARTERSNAKE Thamnophis eques
Cane toad
Bufo marinus
Xenopus
African clawed frog
Amphibian Conservation
CI Diversity
Hyla regilla
Batrachoseps nigriventris
Bufo boreas
CI Diversity
Rana draytonii - California Red legged Frog
a declining species
