Myxopterus - PowerPoint PPT Presentation

Title: Myxopterus


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Myxopterus Devonian invertebrate Predator That
potentially preyed on ostracoderms
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Evolution of jaws from pharyngeal (gill) arches
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Autostylic palatoquadrate fused to cranium
Hyostylic- Palatoquadrate loosely bound to
cranium, Jaw angle supported by hyoid See Fig
5-5
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Hyostylic Jaw at work!
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Evolution of paired appendages
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Chondrichthyes Holocephalans ratfish,
chimaera Fig 5-9
Autostylic
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Elasmobranchs plate gills sharks, rays skates
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Pleurotreme sharks Fig 5-4
Hypotreme skates and rays Fig 5-8
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Chondrichthyean evolutionary relationships

Galeomorphs
Squalimorphs
Neoselachiii
Batoidea
Holocephali
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3 major evolutionary radiations what was trend?
Fig 5-1, 5-2, 5-3
Cladoselache
Carcharodon
Hybodus
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Shark skin - scales and teeth dermal derivatives
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Cartilaginous vertebral column with neural and
hemal arches and some calcification. Notochord
is replaced
Trunk vertebra (no hemal arch)
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Sensory Systems and Feeding
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Olfaction a flow-through nostril! smell blood
from a kilometer away!
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Touch water movement via Lateral Line See
Figure 4-4
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Vision Large eyes with tapetum and nictitating
membrane
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Electrical Ampulla of Lorenzini See Fig 4-7
understand Fig 4-8 experiment
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Mammals
Shark brain size
Birds
Sharks
Brain mass
Fish
Body mass
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Reproduction internal fertilization with
claspers on male pelvic fins Fig 5-6
Oviparous
Ovoviparous or Viviparous
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Japanese marine park captures rare shark on
film
Ancient??