“Reptile” Diversity and Evolution

George A. Lozano

Department of Biology

University of Ottawa

George A. Lozano2

Summary

� Sauropsids

� Turtles

� Diapsids/Saurians

� Plesiosaurs† and ichthyosaurs †

� Lepidosaurs� Tuatara

� Squamates (snakes, geckos, iguanas, monitors)

� Archosaurs (crocodiles, dinosaurs, pterosaurs)

� Dinosaurs

Amniota

Synapsida Sauropsida

Diapsida Turtles

Ancestral amniotes & Turtles

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Turtles - Testudina

� 250 species

� Carapace (vertebrae and ribs)

� Appendicular girdles INSIDE the shell

� Beak, no teeth (along with aves)

� Ear ossicle ���� columella (ind?)

Sauropsida

Diapsida/Sauria Turtles250

Ichthyosaurs† Plesiosaurs†Archosaurs9.1K

Lepidosaurs7K

Ear ossicle ���� collumella, 3rd ind. evol.)

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Lepidosaurs

� “scaly” reptiles

� 6700 species : 4000 lizards, 2700 snakes

� Tuatara: ancestral diapsid skull

� Squamata: derived diapsid skull, hemipenes� Iguanas

� Geckos

� Snakes

� Skinks

� Gila monsters, monitor lizards, Komodo dragon

Euryapsid:

Plesiosaur

Ichthyosaur

Squamates

Snakes

Tuatara

Turtles

AvesModified

diapsid

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Sauropsida

Diapsida Turtles

Crocodiles

Archosaurs

Pterosaurs†Dinosaurs

Theropods

Dinosaurs

Ornithischians†

•Ceratopsids

•Duck-billed dino

•Stegosaurus

•Ankylosaurus

Saurischians

Sauropods†

Theropods

Dinosaurs

Ornithischians†

•-ceratops (uni, tri…)

•Duck-billed dino

•Stegosaurus

•Ankylosaurus

Saurischians

Sauropods†

•Diplodocus

•Brachiosaurus

T. rex† Velociraptor† Birds

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Sauropod and ornithischian (ankylosaurus)

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Theropods

Dinosaurs

Ornithischians†

•Ceratops (uni,tri…)

•Duck-billed dino

•Stegosaurus

•Ankylosaurus

Saurischians

Sauropods†

•Diplodocus

•Brachiosaurus

T. rex† Velociraptor† Birds

9.1K

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You know what a bird is, but…

� Extant dinosaurs

� Feathers

� Flight

� Extensive bone fusion

� No teeth

� Long flexible neck

� Hollow bones

� Extremely high metabolism

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Theropods

Sauropsida

Diapsida Turtles

Ichthyosaurs†

Crocs23

Tuatara

2

Plesiosaurs†Archosaurs Lepidosaurs

SquamataPterosaurs†Dinos

Ornithischchians† Saurischchians

T. rex† Velociraptor†

Sauropods†

Birds

9.1K

Sauropsida Diapsida

Archosaurs

Dinosaurs Saurischians

Lepidosauria

Theropods Squamata

Bird

s (aves)

Velo

cirapto

r†

T. rex

†

Sau

ropods

†

Orn

ithisch

ians

†

Ptero

sauru

s†

Cro

codilia

Ichth

yosau

ria†

Plesio

sauria

†

Snak

es

Geck

os

Iguan

as

Monito

r lizzards

Tuatara

Turtles (testu

din

a)

Tetrapods Amniotes

Sauropsida Diapsida

Archosaurs

Dinosaurs

Synapsida

Saurischians

Lepidosauria Mammalia

Amphibia

Theropods Squamata Theria Batrachian

Bird

s (aves)

Velo

cirapto

r†

T. rex

†

Sau

ropods

†

Orn

ithisch

ians

†

Ptero

sauru

s†

Cro

codilia

Ichth

yosau

ria†

Plesio

sauria

†

Snak

es

Geck

os

Iguan

as

Monito

r lizzards

Tuatara

Turtles (testu

din

a)

Euth

eria

Metath

eria

Monotrem

ata

Sailb

ack sy

nap

sids

†

Fro

gs

Salam

ader

Caecilian

s

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© George A. Lozano