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).