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Synapsida Therapsida Theriodontia
Gorgonopsia Therocephalia Cynodontia
Eupelycosauria
Dinocephalia Dicynodontia Pelycosauria (paraphyletic)
Anapsida Diapsida
Amniota
Eureptilia
Edaphosaurids Sphenacodontids
Synapsida Anapsida Lepidosauria Archosauria Diapsida Eureptilia - - PowerPoint PPT Presentation
Synapsida Anapsida Lepidosauria Archosauria Diapsida Eureptilia - - PowerPoint PPT Presentation
Synapsida Anapsida Lepidosauria Archosauria Diapsida Eureptilia Amniotes (paraphyletic) Therocephalia Pelycosauria Gorgonopsia Dicynodontia Dinocephalia Cynodontia Sphenacodontids Edaphosaurids Theriodontia Therapsida
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Pelycosaurs: Early Permian
Eothyris Cotylorynchus Edaphosaurus Dimetrodon Edaphosaurids Sphenacodontids
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Tetraceratops Moschops Lystrosaurus Arctognathus
- Basal
- Dinocephalia
- Dicynodontia
- Gorgonopsids
- Mammal Ancest.
Cynodontia
Therapsida: Mid-Late Permian
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Amniotes Synapsida Diapsida Anapsida Eureptilia Lepidosauria Archosauria
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Anapsids
- Late Permian
Scutosaurus
Pareiasaurs
- Vegetarians
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Diapsida Lepidosauria Archosauria Diapsids in the Permian Weird, Wonderful, and Rare
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Coelurosauravus Protorosaurus Prolacertiform Petrolacosaurus basal Diapsid Sharovipteryx Prolacertiform
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The Permo-Triassic Extinction: The ‘Great Dying’
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251 Ma
50% of marine families were lost across the Permo-Triassic @ 151 Ma scales to ca. 90% species loss in the sea
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The ‘Death Curve’
Marine Invertebrates
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What caused the extinction event?
Karoo Basin, South Africa Permian Dicynodon Zone Triassic Lystrosaurus Zone
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Plant Dieback => Catastraphic Erosion
Hypothesis: Plant Dieback Evidence:
- Increased erosion
- Fungal explosion
- Worldwide distribution
- Coal Gap
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Slow Terrestrial Floral Collapse- Greenland Pollen/Spore Cores
- Fungal activity followed loss of forests and herbaceous veg
- Successional weedy vegetation takes hold
- Fern and cycad expansion
- Most successional plants vanish, lycopsids remain
- Plant abundance is drastically reduced (few pollen/spores)
500,000 to 600,000 years
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If plant collapse initiated terrestrial extinctions, what caused the plant collapse???
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Flavor of the Day: The Siberian Traps
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Lystrosaurus: the Disaster Taxon
Expansion
- Few herbivorous competitors
- Few carnivorous predators
95% terrestrial faunas!
- @ 1 meter, the largest animal on earth
There was probably nothing ‘special’ about Lystrosaurus... It was just lucky... this is a pattern in extinction events.
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Other animals obviously survived... Low abundance => poor fossil documentation
Temnospondyl amphibians Mastodonsaurus (aquatic)
Fully terrestrial animals communities did not recover for ca. 30 Ma
Proterosuchus Archosaur Cynognathus early Triassic synapsid Dicynodonts Cynodonts Remained important Herbivores
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Refugia
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Urochordata Cephalochordata Assorted jawless fish Most ‘fishes’ Most ‘amphibians’ Synapsids Anapsids Lepidosaurs Archaic archosaurs Crocodiles Pterosauria Dinosauria
Chordata Vertebrata Gnathostomata Tetrapoda
Archosauromorphs
Amniotes
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The RISE of the ARCHOSAUROMORPHS!
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Rhyncosauria
early Triassic VERY abundant Herbivorous Pen-Knife Premaxilla/Dentary vs. ‘rostral bone’ Precision Shear
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Amniotes Synapsida Diapsida Anapsida Eureptilia Lepidosauria Archosauria
Archosauromorpha
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Archosauria Crown-clade Archosauria Ornithodira
Crurotarsi Ornithosuchidae Pterosauria Dinosauria “Rauisuchia” Crocodylomorpha Basal archosaurs
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Basal archosaur? Maybe... or it split off before archosauria
Tanystropheus Prolacertiform Archosauria prolacertiform? Archosauromorpha
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Archosauria: synapomorphies Antorbital fenestra (in front of eye) Teeth with serrated margins Mandibular fenestra
Proterosuchus Basal Archosaur
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Euparkeria Derived, Basal Archosaur Bony dermal plates down back