reptilia a very brief history reptiles: what are they? n possess an amniotic /cleidoic egg....

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Reptilia A Very Brief History

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Page 1: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptilia

A Very Brief History

Page 2: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptiles: What are they?

Possess an amniotic /cleidoic egg.– Amnion– Chorion– Allantois– Yolk sack– Reptilian/Monotreme

vs. eutherian placentas.

Cleidoic eggs.– Leathery egg which

is often pervious to water.

– Egg becomes calcified and impervious to water.

– Necessitates internal fertilization.

Page 3: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 4: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 5: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 6: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptiles: What are they?

Possess an intromittent organ.– All sauria and

serpentes have hemipenes.

– Other groups (Chelonians, Crocodylians, and Sphenodon) have a different structure.

– Intromittent organ increases chance of fertilization.

– Reduces sperm loss.– Increases probability

of reproductive success.

– Increases cost of reproduction for female.

Page 7: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptiles: What are they?

Pulmonary respiration.– Increased surface

area in lungs.– Changes in

circulation: 3.5 chamber heart.

– Increased rigidity of ribs?

One occipital condyle!– (amphibians have 2).– Atlas and axis, with

organization of centra.

– Pleurocentra instead of intercentra.

– Maintain osseous strength while enhancing cranial mobility

Page 8: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptiles: What are they?

2 sacral vertebrae. Epidermal scales

– Arise as dermal evaginations.– Contain both alpha and beta keratin. Beta

keratin is found only in reptiles. Nerve endings in epidermis are

expanded at tips, not tapered as in all other vertebrates.

Page 9: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptiles: What are they?

Nictitating membranes over eyes. Intraocular muscles of iris are striated,

not smooth. Tabular bone of skull is separated from

opisthotic. Suborbital fenestra Posttemporal fenestra

Page 10: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 11: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 12: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 13: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 14: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Reptiles: What are they?

Absence of anterior coronoid bone in lower jaw.

Cervical vertebrae have midventral keels.

In adults, second intercentrum fuses to the axis.

Evolution within the skull.

Page 15: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 16: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

What are the consequences of a reptilian mode?

Divorce from water.– Increased foraging options.– Increased exposure to thermal variation.– Higher operating temperatures.– Increased metabolic efficiency.

Page 17: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

Earliest fossils come from mid-Pennsylvanian of Nova Scotia.– Includes relatively small aminals:

Pelycosaurs (Archaeothyris) and romeriids (Hylonomus and Paleothryis).

Pelycosaurs became important in the Permian: This is the lineage that ultimately leads to the therapsida, and then the mammals.

Page 18: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Westlothiana lizziae: E. Carboniferous of Scotland - earliest known sistertaxon to amniotes.

Page 19: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

The Synapsida:– These pelycosaurs were very successful in

the Permian. There were 6 families. Initially they were small, but later became much larger (c. 3m+). Included good carnivores and herbivores as well. Initially, very lizard-like. Included Ophiacodon and Dimetrodon.

Page 20: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

The Synapsida:– Some Pelycosaurs (Ophiacodon,

Dimetrodon, and Edaphosaurus) were sail backed. The sails were supplied with blood, as evidenced by grooves on neural arches – presumably for blood vessels. How would the sails have worked as thermoregulatory structures? What are the other hypotheses (since not all large pelycosaurs had sails)?

Page 21: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 22: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

The Synapsida:– Pelycosaurs died out at the end of the

Permian, at the same time that the Therapsids had an adaptive radiation.

Page 23: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 24: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Characters

1) Sacrum w/ more than 1 vertebra

Page 25: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes Paleozoic Reptiles:

– The anapsida are the first offshoots of the reptilia that we understand (Parareptiles fit in somewhere, but where?).

– Anapsida includes the turtles and the Captorhinids. We have an extremely limited fossil record of the turtles. We know that the Testudines must have been present, but we have no fossils. This may be related to their habits, and consequently poor chance of fossilization.

Page 26: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

Cont:– Captorhinids are lizard-like, they are not

turtles. They had relatively big heads, and they had teeth. Turtles do not have teeth. Is it possible that ‘turtleness’ had not yet evolved? What would be required for a turtle to evolve its shell?

Page 27: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 28: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 29: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 30: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 31: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 32: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 33: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 34: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 35: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 36: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Pre-diapsid Romeriids:– Petrolacosaurus (Araeoscelida). Lizard-

like. Probable good carnivore. Fore and rear limbs of near equal size. Dissapear in early Permian. Diapsid radiation really takes off in the Triassic.

Radiation of Early Amniotes

Page 37: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

Parareptiles:– Origin is uncertain. This seems to be a

garbage group. It is possible that all forms represent independent origins for the Romeriids.

– Lumped with Sauropteryginas and Ichthyosaurs.

– Adaptive radiation off all parareptiles occusrs in the Mesozoic.

Page 38: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes

Parareptiles:– Mesosaurs are from the early Permian.

Marine, gharial-like, with a length of about 1m. Undulatory swimmers with laterally compressed tails. (Think about how to swim with a reptilian body plan).

– Millerosaurs are from the late Permian. Lizard-like, small, similar to modern Iguanids.

Page 39: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Radiation of Early Amniotes Parareptiles:

– Pareiasaurs and Procolophonoids. Pareiasaurs are from the mid to late Permian, while the Procolophonoids are from the late Permian through the late Triassic.

– Pareiasaurs were up to 3m, columnar limbs, robust bodies. Laterally compressed, closely spaced teeth with leaf shaped crowns. Probable herbivores.

– Procolophonoids were smaller and lizard-like, similar to Sauromalus in appearance. Widely spaced crushing teeth.

Page 40: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 41: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 42: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 43: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 44: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 45: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 46: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 47: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 48: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 49: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 50: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 51: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 52: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 53: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 54: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 55: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 56: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 57: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 58: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 59: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 60: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 61: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 62: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 63: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 64: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 65: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 66: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Quadrupedal Ornithischians

Page 67: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Bipedal Ornithischians

Page 68: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Saurischian Theropods

Page 69: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme

Saurischian Sauropodomorphs

Page 70: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 71: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme
Page 72: Reptilia A Very Brief History Reptiles: What are they? n Possess an amniotic /cleidoic egg. –Amnion –Chorion –Allantois –Yolk sack –Reptilian/Monotreme