part 6 - class amphibia and tetrapod origins. class amphibia (sensu stricto) 3 living orders

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