Stuart S. Sumida Biology 342
Phylogeny of Basal Amniota What we used to think...
Mammals Birds
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.