Tiktaalik roseae Edward B. Daeschler, Neil H. Shubin and Farish A. Jenkins, Jr (6 April 2006). A Devonian tetrapod-like fish and the evolution of the tetrapod body plan. Nature 440: 757–763. DOI:10.1038/nature04639.

III. Amphibian evolution - Lissamphibia

A. Synapomorphies of Lissamphibia Hearing apparatus: Stapes is directed dorsolaterally from the fenestra ovalis & operculum present (caecilians?) Articular surface of the atlas is convex Exocipital bones have a suture articulation to the dermal roofing bones Hand has 4 digits and foot has 5 digits

B. Extinct tetrapods and their relationship to Lissamphibia??? Late Carboniferous – “explosion of tetrapod diversity” Lepospondyls & Temnospondyls (>200 genera), all taxa are highly derived when they first appear in the fossil record (no intermediates) Lissamphibians in whole, or part could be most closely related to either of these groups

1). Lepospondyls – Mississippian to lower Permian, 60 genera lack an otic notch they lack labyrinthine infolding in the teeth the centrum of lepospondyls is large and cylindrical usually have a single central element (at least in the presacral series), There are 4 major groups of lepospondyls: Aïstopoda, Nectridea, Microsauria, and Lysorophidae.

2. Temnospondyls – Mississippian to lower Jurassic Bipartite vertebral centrum labyrinthodont teeth (sharp, pointed teeth with a complex folding of the wall of the pulp cavity)

Triadobatrachus – 245mya Virealla, 190 mya

Hypothesis 1

Hypothesis 2

C. Within Amphibia, what is the correct phylogeny? Uncertainty derives from the long time gap between the potential Temnospondyl ancestors in the upper Carboniferous and the occurrence of all 3 extant groups in the early to middle Jurassic.

D. Extant amphibians pair of sensory papillae two sound transmission channels in the inner ear (stapes-basilar papilla channel & opercular-amphibian papilla) specialized visual cells presence of 2 types of skin glands fat bodies that develop from the germinal ridge of the embryo and retain an association w/the gonads in adults

IV. Evolution of reptiles

A. Reptiles – life on land specific events occurring during the Carboniferous period (354-290 mya) – ability to live on land totally…

B. Necessary steps leading up to the amniotic egg

New Extra-embryonic Membranes amnion innermost membrane encloses embryo in amniotic fluid supports body in fluid for normal development allantois storage sac for nitrogenous wastes off of cloaca protects embryos from toxic buildup parts of it may fuse with chorion chorion outermost membrane encloses all others + embryo chorioallantois membrane - merger forms a vascularized gas exchange membrane attached to egg shell or to a placenta

C. Some synapomorphies of amniota embryonic membranes (amnion, chorion, allantois, yolk sac) Scaled skin –cutaneious respiration Complete Rib Cage – signals the use of a thoracic respiratory pump for ventilation of the lungs (nolonger buccal pump) Change in vertebral structure – more robust supporting arch Pleurocentrum becomes main component, neural archers broaden

Ancestor to the amniotes, primarily aquatic… Anthracosauria Ancestor to the amniotes, primarily aquatic… Possess features present in amniotes but not in later amphibians, highly aquatic.

Probably sister taxa to Amniotes & Amphibia

Synapormorphies of extant Reptilia

Anapsids: Testudines (Chelonia) Sauropterygia – sister taxa to turtles??? Molecular evidence supports this hypothesis

Diapsids Lepidosauromorpha Archosauromorpha Rynocephalia Squamata Archosauria