Reef Paleontology and

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Reef Paleontology and Coral Evolution
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Taxonomy of Symbiosis
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Taxonomy of Symbiosis
Clade A
Clade B
Clade C
Clade D
Clade F
Clade G
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Naming Corals
Hermatypic ? build reefs and possess
zooxanthellae ( zooxanthellate)
Ahermatypic ? dont build reefs or possess
zooxanthellae ( azooxanthellate)
BUT
- not all zooxanthellate corals build reefs
- some azooxanthellate corals build reefs
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Naming Corals
z-corals ? possess zooxanthellae (
zooxanthellate)
az-corals ? dont possess zooxanthellae (
azooxanthellate)
Third group
- can exist with or without symbionts
(facultative)
Apozooxanthellate
e.g. Oculina
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Middle to late Precambrian
Algal Reefs - From cyanophytes
-layer of algae forms
-sediment is trapped
-a second algal layer grows
- more sediment is trapped
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Middle to late Precambrian
Algal Reefs - Stromatolites
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Precambrian-Cambrian Transition
Archaeocyathan Reefs
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Ordovician
Solenopora -a coralline algae
Colonial Bryozoa
Stromatoporoids (stony sponges)
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Ordovician (2)
Stony cnidarians - first of corals
Tabulate form
Rugose form
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Stable association for 130 my
coral
sponge
algae
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Late Devonian - Early Carboniferous
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Mid Carboniferous - revitalized assemblage

Crinoids
Brachiopods (lamp shells)
Sponges
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Permian Extinction
Ended the second successful reef association
bryozoan
sponge
algae
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Evolution of sceractinian corals
originations
extinctions
Jurassic
Triassic
Number of species
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Evolution of sceractinian corals
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Jurassic
Scleractinian corals
Coralline algae
Stromatoporids
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Jurassic Tethys Sea
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Cretaceous
Rudists
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Cretaceous
Rudists
Scleractinian corals
Stromatoporids
Coralline algae
30 my
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Cretaceous-Tertiary Boundary
-meteorite hits earth
Mass extinctions
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Cretaceous-Tertiary Boundary
Scleractinian corals
Coralline algae
Rudists
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Cenozoic - Palaeocene
z-corals more severely affected
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Why loss of coral diversity?
Temperature decline
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Cenozoic - Eocene
Regeneration of z-coral type reefs
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Eocene to Present
Five distinct faunal periods
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Evolution of Scleractinia
Problem
?
Permian extinction
First scleractinian fossils
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Evolution of Scleractinia
Hypotheses for Ancestor of Scleractinia
1) Rugosan
-came from some rugosan ancestor
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Evolution of Scleractinia
Hypotheses for Ancestor of Scleractinia
1) Rugosan
-came from some rugosan ancestor
Problems
Rugose coral Scleractinian
Tetrameric Hexameric
Calcitic Aragonitic
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Evolution of Scleractinia
Hypotheses for Ancestor of Scleractinia
2) Scleractiniamorph
Numidiaphyllum
- aragonite ? calcite

• shares structural features with Scleractinia

Problem - 14 my gap
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Evolution of Scleractinia
Hypotheses for Ancestor of Scleractinia
3) Naked coral
- presumes a non-calcifying anemone
Current relationships of scleractinians,
zoanthids, corallimorphs and actinarians
Actinaria
Corallimorphia
Numidiaphyllia
Scleractinia
Zooanthidea
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Evolution of Scleractinia
Hypotheses for Ancestor of Scleractinia
3) Naked coral
- presumes a non-calcifying anemone
Support

• anatomical similarities between living
• Scleractinians and Zoantharians

• molecular similarities between living
• Scleractinians, Actinarians and Zoantharians

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Two major zones of reef diversity
Caribbean
Indo-Pacific
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North American
Caribbean
Bonaire
Cocos
South American
Nazca
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North American
Caribbean
Cocos
South American
Nazca
Subduction
Thrust-fault
Strike-slip
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Bonaire Reefs
Brandaris
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Quaternary
Recent 11,000
Wisconsonian 75,000
Sangamonian 130,000
Illinoisian 180,000
Yarmouthian 380,000
Kansan 410.000
Aftonian 600,000
Nebraskan 800,000 to 1,000,000
limestone cap
undifferentiated terrain
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(No Transcript)
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Bonaire Reefs
Bonaire
Grand Cayman
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Bonaire Reefs
Few sandy beaches