SURVEY OF THE TETRAPODS Class “LABYRINTODONTIA”

Rhipidistia Ichthyostegalia Amniota Lissamphibia Temnospondyli Anthracosauria Lepospondyli Eusthenopteron Ichthyostega Panderichtyes Acanthostega

Class AMPHIBIA Subclass LISSAMPHIBIA

URODELA SALIENTIA GYMNOPHIONA Fish (“Rhipidistian”) - Tetrapod Transition & Fossil Record

Generalized “Rhipidistian”

Transitional “Rhipidistian”

Early Amphibian

•Reduction of fins •Reduction of gills •Shift of eyes (dorsally) •Dactylous appendages History of the AMPHIBIA

Surviving amphibians (Lissamphibians)

Primitive “amphibians” (aquatic & terrestrial)

Derived “labyrinthodonts” Terrestrial & ancestral to “reptiles”

Stem Tetrapods Earliest Tetrapod: Acanthostega

Weak vertebral column Poorly formed joints (limbs)

Retains internal gills

Eyes face upward

Tail fin with skeletal supports Polydactylous Limbs Primitive & Derived Labyrinthodonts

Amphibious Icthyostegalian

Anthracosaur Mostly terrestrial (as adults) Stronger backbone Better formed joints (limbs) Skull narrowed; eyes lateral Limbs pentadactylous Subclass LISSAMPHIBIA (modern amphibians)

Order SALIENTIA (=Anura)

Order URODELA (=Caudata)

(Tropical, burrowers)

Order GYMNOPHONIA (APODA) Amniote Skull Types & Classification

Class REPTILIA Subclass PARAREPTILIA = (“Anapsida”) Subclass SYNAPSIDA = (“Synapsida”) Subclass EUREPTILIA = (“Diapsida”)

Modified diapsid skull Subclass PARAREPTILIA

Specialized “Anapsids”: Turtles & Pareiosaurs

Order TESTUDINATA Order PARIESAURIA LEPIDOSAURS: Most Successful Group Modern Reptiles Superorder LEPIDOSAURIA

Order SPHENODONTIA Order SQUAMATA

“Living Fossil”

(Tuatara - New Zealand)

(Lizards)

(Snakes)

Order AMPHISBAENIA (tropical burrowers) Subclass ARCHOSAURIA

Order CROCODILIA

Order PTEROSAURIA

Order ORNITHISCHIA Dinosaur Pelvic Structure & Classification

Convergent with birds Bird - Therapod Connection

Infraclass ARCHAEORNITHYES

Infraclass NEORNITHYES Infraclass ODONTORNITHYES Infraclass NEORNITHYES

Superorder Paleognathae

Infraclass ENANTIORNITHYES Superorder Neognathae Synapsids & Origin of Mammals Fossils from S. Africa & S. America

Cynodont Therapsids = sister group of mammals

Primitive Therapsids

Pelycosaurs = basal mammal-like reptiles MAMMALIA

“REPTILIA” THERIA Cynodont Therapsids PROTOTHERIA METATHERIA EUTHERIA

Basic therian features

•Placenta & viviparity •Therian shoulder complex Basic mammal features •Tribosphenic molars

•Hair •Mammary glands •3 ear ossicles, etc. Prototherians Order Monotremata (Australia)

Metatherians Order Marsupialia (Australia, Americas) Eutheria: Placental Mammals (world-wide distribution)