Stuart S. Sumida Biology 342 Phylogeny of Basal Amniota What we used to think... Mammals Birds “Mammal-like Reptiles” PRIMITIVE REPTILES Amphibians Um.........NO. Mammals Birds “Mammal-like Reptiles” PRIMITIVE REPTILES Amphibians Panderichthyid Most Reptilia Sarcoptrygians Amphibians Diadectomorpha Synapsida (including Aves) Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Amniota? Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Amniota? TETRAPODA Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Amniota? Other Sarcopterygians Panderichthyids Ichthyostegalia Dissorophoids Lissamphibia Sarcopterygii Anthracosauria Tetrapoda Seymouriamorpha Diadectomorpha The road to reptiles Amniota Advanced Seymouriamorpha Amphibian: Seymouria sanjuanensis – from the Early Permian of Europe and the U.S. Amniotes: have four embryonic structures that reside outside the embryo to help it survive: •Amnion •Yolk sac •Chorion •Allantois Other Sarcopterygians Panderichthyids Ichthyostegalia Dissorophoids Lissamphibia Sarcopterygii Anthracosauria Tetrapoda Seymouriamorpha Diadectomorpha The road to reptiles Amniota Diadectomorpha: •No intertemporal bone like other amniotes •Very terrestrially adapted Orobates pabsti, a new genus of diadectomorph– found in both North America and central Germany Orobates pabsti, a new genus of diadectomorph– found in both North America and central Germany 10 cm Orobates pabsti, a new genus of diadectomorph– found in both North America and central Germany 1 cm Diadectes – this genus found in Utah, New Mexico, Texas, Oklahoma, and central Germany “Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Reptilia Amniota Amniotes: have four embryonic structures that reside outside the embryo to help it survive: •Amnion •Yolk sac •Chorion •Allantois Remember, we’re studying AMNIOTES. Defined by: EMBRYOLOGICAL FEATURES: amnion, chorion, allantois, yolk sac. ANATOMICAL FEATURES: lack of an intertemporal bone. ALSO, FUNCTIONAL FEATURES: •Costal breathing (inhaling using movement of the ribs). •Active exhalation using movement of ribs to push air out. “Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Reptilia Amniota Basal Synapsida (“Pelycosauria”): A single opening on side of skull “Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Reptilia Amniota PARAREPTILIA Includes: •Mesosauria •Bolosauridae •Procolophonia •Paraiesauria Mesosaurus: A member of Mesosauria Eudibamus cursoris (a bolosaur) The earliest known bipedal vertebrate From the Early Permian (~280 million years old) of central Germany. Bradysaurus: A member of the Parieasauria Parieasaurs have lumpy, bumpy skulls Scutosaurus “Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Reptilia Amniota Basal Captorhinid: Eocaptorhinus 1 cm New taxon: (Albright, in prep) New, miniature, captorhinid with three rows of dentary and maxillary teeth. 1 cm Size Range in Captorhinid Reptiles 1 cm New taxon (All specimens collected by Everett C. Olson.) “Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Reptilia Amniota Basal Diapsid: Petrolacosaurus Note: TWO holes (fenestrae) on side of skull Known back to Late Pennsylvanian Diapsida includes: •Many extinct forms •Squamata •Archosauromorpha Squamata includes living lizards and snakes. .