Slide #1.

The Anapsids and Diapsids
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Slide #2.

The Amnion Image from: http://www.ucmp.Berkley.edu
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Slide #3.

Relative diversity of living vertebrates
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Slide #4.

We are here
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Slide #5.

Parareptilia (Olson 1947) • An extinct group among basal amniotes • Upper Pennsylvanian to Upper Triassic • Do not have a temporal fenestra and have been called Anapsida (Williston 1917) when the taxon included the turtles.
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Slide #6.

Parareptilia (Olson 1947) These varied from small aquatic to large terrestrial forms Procolophon, broad and flattened burrowing animals from the upper Permian to the Triassic. Image by Arthur Weasley, Wikipedia Mesosaurus, a small aquatic animal. Scutosaurus, a pareisaur, once thought to be the group from which the turtles emerged. Image by Nobu Tamura Image by Arthur Weasley, Wikipedia
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Slide #7.

Diapsida (Osborn 1903) • 2 temporal fenestrae • Relatively long radius in most • This group includes all reptiles and birds, a taxon called Sauropsida (Watson 1956)
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Slide #8.

Class Eodiapsida • These are the basal diapsids and include 2 very different groups: • Younginomorpha (Pennsylvanian to Lower Triassic) • Ichthyosauromorpha (Mid Triassic to Mid Cretaceous) ? The relationship between the two groups that are merged here to create the Eodiapsida, a sister group to the Lepidosauromorpha and Archosauromorpha. In general, this figure is based on Benton (2005) and shows the relationship between this group and the other higher taxa of gnathostomes.
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Slide #9.

Class Eodiapsida • Younginomorpha • Lizard-like amniotes Petrolacosaurus, the earliest known diapsid. Image from: http://taggart.glg.msu.edu/isb200/carbfor.htm
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Slide #10.

Class Eodiapsida • Ichthyosauromorpha • Aquatic and cetacean-like • Skull lost the lower fenestration Utatsusaurus of the early Triassic was one of the earliest known ichthyosaurs. Note the elongate body, paddle-like limbs, and the small fin on the tail. Shonisaurus of the upper Triassic was the largest known ichthyosaur with a maximum length of 21 meters. The animal was whale-like and may have been toothless as an adult. Image by: © Arthur Weasley; Creative Commons Image by: © Arthur Weasley Platypterygius, the last known ichthyosaur, lived in the Cretaceous. They had very large pectoral paddles, powerful tails, and streamlined bodies. Platypterygius grew to 7 meters long and hunted in the open ocean. Image by: Dimitry Bogdanov; Creative Commons
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Slide #11.

CLADOGRAM OF THE LEPIDOSAUROMORPHA MAJOR CLADES OF THE LEPIDOSAUROMORPHA 1. Sauropterygian Clade 2. Lepidosaur Clade 3. Sphenodont Clade 4. Squamata Clade 5. Serpentes Alternate Clades
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Slide #12.

The Sauropterygian Clade Placodont Plesiosaur
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Slide #13.

Sphenodonts, the Basal Lepidosaurs A living sphenodont, the Tuatara
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Slide #14.

Squamata Clade, the Lizards • Five assemblages are identified • • • • • Iguania Gekkota Amphisbaena Anguimorpha Scincomorpha Gecko Mosasaur Iguana BlueTongued Skink Glass Lizard Komodo Dragon
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Slide #15.

The Serpentes Indian Python Indian Spectacled Cobra All living snakes seem to have been derived from Iguanids, but no living Iguanids are legless.
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Slide #16.

CLADES OF THE ARCHOSAUROMORPHA 1. RHYNCHOSAURIA, THE BASAL ARCHOSAURS 2. CROCODILIANS 3. PTEROSAURS 4. DINOSAURS 5. ORNITHISCHIANS 6. SAURISCHIANS 7. SAUROPODS 8. THEROPODS 9. THE BIRDS
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Slide #17.

Rhynchosaurs, beaked archosaurs  Protorosaurus, a long-necked rhynchosaur from the  upper Permian. Hyperodapedon, a strange basal Archosauromorph  that was a herbivore.  Notable adaptations included a  distinctive narrow beak, specialized cheek teeth, and  hind claws adapted to digging. 
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Slide #18.

Crocodilians, archosaurs with rotating ankle Euparkeria, a stem Archosaur from the middle  Triassic.   Photo of an American Alligator in Florida. 
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Slide #19.

Pterosaurs, the finger-winged archosaurs An illustration of Rhamphorhynchus in a dive.  A Pteranodon in flight. 
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Slide #20.

The Dinosaurian Clade • longer hind legs than front legs • the skeleton and musculature of the hind legs that causes them to be underneath the body rather than splayed, including the distinct offset head an ball of the femur • a reduction of the digits in the manus and pes (usually to 3 or 4) • an acetabulum, hip joint, that has a hole in the center • a sacrum of at least 3 fused vertebrae • a reduced fibula • a crest that runs much of the way down the humerus for the attachment of the deltoid and pectoral muscles Weishampel et al. (1990), Soreno (1999), and Benton (2005) 
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Slide #21.

Brusatte, S.L., S.J. Nesbitt, R.B. Irmis, R.J.Butler, M.J. Benton, and M.A. Norell. 2010. The origin and early radiation of dinosaurs. Earth-Science Reviews 101(1-2): 68-100. Fig. 2. A cladogram of the major groups of archosaurs. Archosauria is divided into two major groups, the crocodile line  (Crurotarsi) and the bird line (Avemetatarsalia). The crocodile line is further subdivided into several subgroups (the longsnouted and semi-aquatic phytosaurs, the heavily armored aetosaurs, the mostly predatory rauisuchians, and true  crocodylomorphs), whereas the bird line includes dinosaurs, birds, and a handful of close “dinosauromorph” cousins.  Silhouettes not to scale. Cladogram delineated by Simon Powell, University of Bristol.
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Slide #22.

Brusatte et al. (2010) Fig. 3. Skeletal reconstructions of four Late Triassic–Early Jurassic dinosaurs, representing the major subgroups of early dinosaurs. These reconstructions are designed to provide a general guide to early dinosaur skeletal anatomy, and should not be used for fine-scale anatomical comparison or character state scoring in phylogenetic analysis. A, Herrerasaurus ischigualastensis (Dinosauria incertae sedis, possibly a theropod or stem saurischian outside the theropod + sauropodomorph clade); B, Dilophosaurus wetherilli (Theropoda); C, Saturnalia tupiniquim (Sauropodomorpha); D, Heterodontosaurus tucki (Ornithischia).
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Slide #23.

Benton, M.J., J. Forth, and M. Langer. 2014. Models for the rise of dinosaurs. Current Biology 24(2): R87-R95. Figure 3. Time-calibrated  phylogeny of the first dinosaurs  and their closest relatives. The figure also shows some key evolutionary  acquisitions. Orange depicts known range of  fossil records for each clade; ghost lineages  (missing fossil record implied by sister group)  in blue. (A) Phylogeny of basal dinosaurs and  their nearest relatives, plotted against  geological time. (B–E) ‘Typical’ dinosaur or  dinosauromorph traits: (B) filamentous  integumentary cover in the tail of the  ornithischian Psittacosaurus[74]; (C)  fibrolamellar cortical bone (arrow) in the femur  of Saturnalia[75], indicative of rapid growth; (D)  pneumatic foramen for air sac diverticuli  (arrow) in a vertebra of the  theropod Majungasaurus[76];  (E) Silesaurus reconstructed in bipedal stance  [77], although this posture is debated.  Positions in the cladogram where those  features first appear are tentatively indicated,  but the conditions in surrounding taxa are  mostly ambiguous. Based on phylogenies of  basal dinosaurs [34], where herrerasaurids are  placed as basal saurischians rather than basal  theropods, as sometimes suggested [32].
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Slide #24.

Ornithischian Clade Painting of an ornithopod hadrosaur, a member of the  ornithischian dinosaurs. The animal has a bipedal  stance, but it can also move about as a quadruped.  An image of Triceratops, which was an obligate quadruped.
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Slide #25.

Saurischian Clade Tyranosaurus, one of the last theropod non-avian dinosaurs Diplodocus, one of the giant sauropods had pillar-like  legs, an enormous body, and long neck and tail.  As  illustrated here, the animals likely walked with their  tails elevated, which served as a counterbalance.  
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Slide #26.

Avian Dinosaurs Hand of Deinonichus (L) and Archaeopteryx (R) Passer domesticus, the most widespread living theropod
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Slide #27.

Major Events in the Evolution of Flying Theropods, Birds Archaeopteryx
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Slide #28.

Busatte, S.L., J.K. O’Connor, and E.D. Jarvis. 2015. The origin and diversification of birds. Current Biology 25: R888-R898. Figure 1. Summary phylogeny (genealogical tree) of birds. The phylogeny shows where birds fit into the larger  vertebrate family tree and the relationships of the earliest  birds and their closest dinosaurian relatives (based on [2]  and other studies cited therein). Timescale values are in  millions of years; thick red line denotes the mass  extinction at the Cretaceous–Paleogene boundary caused  by asteroid impact (denoted by fireball on the right);  arrows denote lineages that survived the extinction;  circles represent species known from a particular point in  time; thick line sections of branches indicate direct fossil  evidence and thin lines are temporal distributions implied  by phylogenetic ghost lineages; Cz, Cenozoic interval  after the end-Cretaceous extinction. Silhouette anatomical  features in the lower part of the figure are plotted  approximately where they evolve on the phylogeny. Species  silhouettes at the top of the image are from phylopic.org and designed by  (from left to right): Nobu Tamura, Anne Claire Fabre, T. Michael Keesey,  Steven Traver, Andrew A. Farke, Mathew Wedel, Stephen O’Connor/T. Michael  Keesey, Brad McFeeters/T. Michael Keesey, Scott Hartman, T. Michael Keesey,  Scott Hartman, Scott Hartman, Matt Martyniuk, Matt Martyniuk, Matt  Martyniuk, Matt Martyniuk, Nobu Tamura/T. Michael Keesey, Matt Martyniuk,  J.J. Harrison/T. Michael Keesey. ‘Bipedal posture’ silhouette by Scott  Hartman.
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Slide #29.

What about turtles?
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Slide #30.

Views of Turtle Evolution Three different cladograms regarding the relationships of the living amniotes.  Cladogram A assumes that the  turtles are sisters to the diapsids.  Cladogram B assumes that the turtles arose from within the diapsids.   Cladogram C assumes that the turtles arose from a basal line of amniotes. A=Anapsid; AM=Amniote; D=Diapsid;  S=Synapsid.
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Slide #31.

Pleurodires (side-necked turtles) Matamata, a pleurodire or side-neck turtle from South  America.
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Slide #32.

Cryptodires, S-Necked Turtles A softshell turtle, a trinochoidean cryptodire. A sea turtle, a chelonoidean cryptodire.  An Aldabra Tortoise, a  testudoidean cryptodire.
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Slide #33.

Early Turtles Restoration of Odontochelys, one of the oldest turtles. Developmental and molecular evidence suggests that they evolved from within the diapsids. Are they Lepidosaurs or Archosaurs? Adapted from Lee (2013) Adapted from Schoch and Sues (2015)
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