Komodo Dragon (Varanus Komodoensis) Phylum Chordata Subphylum Vertebrata Class Reptilia Order Squamata Family Varanidae

Home , Salvator (lizard), Tupinambis, Varanus (Odatria)

Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Komodo dragon (Varanus komodoensis) Phylum Chordata Subphylum Vertebrata Class Reptilia Order Squamata Family Varanidae

Varanus komodoensis feeding on water buﬀalo (Wikipedia) Varanus salvator CT scan from DigiMorph Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114

BBC Video “Komodo Dragons attack” https://www.youtube.com/watch?v=gcTg9mt4eAk Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Komodo dragon (Varanus komodoensis) CT scans available from http://www.digimorph.org/

Parietal Frontal

Nasal Lach- rymal Pre- Maxilla Jugal maxilla

Quadrate

Articular Surangular Dentary Angular

Varanus salvator CT scan from DigiMorph Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Jaw muscles and movements in a lizard Black and white tegu (Tupinambis merianae)

Phylum Chordata Subphylum Vertebrata Class Reptilia Order Squamata Family Teiidae

Characteristics of the reptilian bite

1. Jaw joint is located between quadrate and articular bones

2. Lower jaw pivots around end of quadrate like upside down see-saw

3. Posterior muscles pull up on back “handle” of the articular to open jaw

4. Anterior muscles pull up on surangular and other bones to close jaw

5. Muscles originate around temporal openings and insert on jaw Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Phylogeny of Living Vertebrates

Chondrichthyes “Osteichthyes” Agnatha Amphibia Crocodilia Sharks, rays and Ray-finned and lobe- Frogs, Mammalia Chelonia Lepidosauria Lampreys and Alligators, Class Aves chimaeras finned fish salamanders Mammals Turtles Lizards, snakes hagfish crocodiles Birds

Archosauria Diapsida Reptilia

Amniota

Tetrapoda

Synapomorphies (shared derived features) of vertebrates • Bilateral symmetry • Mouth, stomach, and gut • Brain and spinal cord (CNS, central nervous system) • Head with multiple sense organs • Heart and circulatory system ventral to CNS • Pharyngeal pouches (gill arches) • Segmented body with muscles • Skeleton composed of cartilage or bone (collagen with hydroxyapatite mineral), dentine, and enamel • Paired appendages Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114

Era Period Epoch Age (millions of years ago) Holocene Quaternary Pleistocene Mass Extinction 2.6 Pliocene Neogene Miocene 23 Oligocene Cenozoic Eocene Paleogene Paleocene 65 Cretaceous 145 Jurassic 199 Mesozoic Triassic Phanerozoic 251 Permian 299 Pennsylvanian

318 Jawed and tetrapods fish Mississippian Carboniferous 359 Devonian Early tetrapods on land 416 Paleozoic Conodonts Silurian 444

Ordovician Jawless fish 488 Cambrian First vertebrate fossils 542 Proterozoic 2.5 billion Archean 4.6 billion Precambrian Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114

Early Paleozoic (542- 359 Ma) •North America was much smaller than today •Sea level was high, with extensive shallow seas •Oldest parts of the Appalachian Mountains were just forming

Early tetrapods on land

First vertebrates

Hallam, 1984. Annual Review of Earth and Planetary Sciences, 12: 205-243. (c) Ron Blakey (http://jan.ucc.nau.edu/~rcb7/nam.html) Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114

Early Cambrian (540 Ma)

North China

South China

Gondwana Siberia North (Africa + South America America + Australia + Antarctica) Baltica

Early Cambrian (540 Ma)

North China

South China

Gondwana Siberia North (Africa + South America America + Australia + Antarctica) Baltica

(c) Ron Blakey (http://jan.ucc.nau.edu/~rcb7/nam.html) Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Chengjiang, China (Early Cambrian, 520-525 Ma) Haikouichthys • Mouth and gut tube • Dorsal fin Earliest vertebrate • Myotomes (muscle segments) • Gill pouches • Notochord • Heart • Nasal and otic capsules

Shu et al., 1999, Nature, 402: 42-46, Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Chengjiang, China (Early Cambrian, 520-525 Ma) Haikouichthys • Mouth and gut tube • Dorsal fin Earliest vertebrate • Myotomes (muscle segments) • Gill pouches • Notochord • Heart • Nasal and otic capsules

• Tiny early vertebrates • Phosphatic tooth elements are commonly preserved as fossils • Whole animal extremely rare (no bony skeleton) • Phosphatic material changes color with heat, used as “paleothermometer” to study metamorphism and burial of rock • Biostratigraphic markers Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114

Conodont elements (“teeth”) in life position Pandorinellina remscheidensis elements and reconstruction their position in a living animal

(Aldridge and Purnell, 1996. The conodont controversies. TREE, 11: 463-468)

Manticolepis subrecta apparatus in life position (Dzik, 1991, Evolution of oral apparatuses in the conodont chordates. Acta Palaeontologica Polonica, 36: 265-323) Department of Geological Sciences | Indiana University Dinosaurs and their relatives (c) 2015, P. David Polly Geology G114 Phylogeny of early vertebrates

Agnatha, “jawless fish” (paraphyletic) “jawed fish”

Hagfish Lampreys Haikouichtyes Conodonts Heterostraci Anaspida Osteostraci Gnathostomes * jaws

Unnamed * paired fins or fin folds

Unnamed * calcified dermal skeleton Craniata * eye muscles * symmetrical gills * 2 semicircular canals Vertebrata