NatSci360 Fishes

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Natural Sciences 360 Legacy of Life Lecture
11-12 Dr. Stuart S. Sumida
PHYLUM CHORDATA Subphylum VERTEBRATA TETRAPODA
The Water-to-Land Transition
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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Lissamphibia Anthrocosauria
Seymouriamorpha Diadectomorpha Amniota
Sarcopterygii
Tetrapoda
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Panderichthyids were the most tetrapod-like of
the sarcopterygian fishes.
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Other Crossopterygians Panderichthyids Ichthyost
egalia Dissorophoids Lissamphibia Anthrocosauri
a Seymouriamorpha Diadectomorpha Amniota
Crossopterygii
Tetrapoda
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Acanthostega gunneri
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Acanthostega gunneri
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Acanthostega gunneri
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Acanthostega gunneri
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The Earliest Tetrapods (such as
Ichthyostegalians) were Very Fish-like
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Fins or Limbs?
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Fins or Limbs? Yes, polydactylous fins/limbs.
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• The Water-to-Land Transition
• Recall the Problems plants faced
• Dessication (drying out)
• Support out of water
• Reproduction on land

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• The Water-to-Land Transition
• Problems Animals faced
• Dessication (drying out)
• Support out of water
• Breathing
• Locomotion on land

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• How did early TETRAPODS deal with these problems?
• Vertebrae that interlocked more tightly
• Thick, heavily scaled skin
• Fins became stout massive legs (lobe-fins
  preadapted for this)
• Emphasis on lungs instead of gills in adults

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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Lissamphibia Anthracosauria
Seymouriamorpha Diadectomorpha Amniota
Sarcopterygii
Tetrapoda
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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Lissamphibia Anthrocosaur
ia Seymouriamorpha Diadectomorpha Amniota
Sarcopterygii
Tetrapoda
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• Living Amphibians
• All used to be included in a group called
  Lissamphibia
• Lissamphibia was considered a natural group
  because all have similar teeth (pedicillate) and
  all have similar ear bones.
• Lissamphibia included
• Gymnophiona (limbless amphibians)
• Caudata (salamanders)
• Anura (frogs and toads)

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• Gymnophiona (limbless amphibians)

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Caudata (salamanders)
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Caudata (salamanders)
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Anura (frogs and toads)
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Anura (frogs and toads)
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Anura (frogs and toads)
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Anura (frogs and toads)
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Anura (frogs and toads) Scaphiopus couchi
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Anura (frogs and toads)
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NEW INFORMATION!!! It turns out Weve found
some important new fossil material that has given
us the opportunity to reassess the evolutionary
relationships of Lissamphibia. A new animal
now known as Gerobratrachus hottoni was
discovered. From the Early Permian, about 280
million years old, of present-day north-central
Texas Looks remarkably like a frog, but still
has a longer body and a tail like a salamander.
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Gerobratrachus hottoni
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It turns out With the help of Gerobatrachus, we
now know that frogs and salamanders are closely
related, but gymnophionans are convergent in
their dental features. Frogs and salamanders ARE
related to dissorophoid amphibians. Whereas
gymnophionans are probably related to a group
called MICROSAURS.
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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Batrachia
(frogs/salamanders) Anthracosauria Seymouriamorp
ha Diadectomorpha Amniota
Sarcopterygii


Tetrapoda
Microsauria Gymnophiona
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In other words Lissamphibia is not a true
group also known as POLYPHYLETIC
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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Batrachia
(frogs/salamanders) Anthracosauria Seymouriamorp
ha Diadectomorpha Amniota
Sarcopterygii


Tetrapoda
Microsauria Gymnophiona
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Proterogyrinus a highly terrestrial
amphibian Carboniferous Period
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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Batrachia
(frogs/salamanders) Anthracosauria Seymouriamorp
ha Diadectomorpha Amniota
Sarcopterygii


Tetrapoda
Microsauria Gymnophiona
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Advanced Seymouriamorpha Amphibian Seymouria
sanjuanensis from the Early Permian of Europe
and the U.S.
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Other Sarcopterygians Panderichthyids Ichthyoste
galia Dissorophoids Batrachia
(frogs/salamanders) Anthracosauria Seymouriamorp
ha Diadectomorpha Amniota (including reptiles)
Sarcopterygii


Tetrapoda
Microsauria Gymnophiona