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Phylum Chordata. Subphylum Craniata (Vertebrata). Phylum Chordata, Subphylum Vertebrata (Craniata). Increase in brain size & sensory apparati Derivation of neural crest Enclosure of anterior neural tube in cartilage/bone (neural crest derivative)
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Phylum Chordata Subphylum Craniata (Vertebrata)
Phylum Chordata, Subphylum Vertebrata (Craniata) • Increase in brain size & sensory apparati • Derivation of neural crest • Enclosure of anterior neural tube in cartilage/bone (neural crest derivative) • Subsequent derivation of cartilaginous vertebrae, bony jaws & cranium • Ossification of skeleton & derivation of appendicular skeleton • Two superclasses • Agnatha – without jaws • Gnathostomata – mouth with jaws
Subphylum (group) superclass superclass Vertebrate Cladistics
Class Cephalaspidomorphi Lamprey
Ammocoete Larvae of Lamprey • Filter feeders using pharyngeal slits
The terrifying development from the terrifying pharyngeal pouches
Class Chondrichthyes Subclass Elasmobranchii • sharks & skates & rays • Skates • Fleshy tail, 2 dorsal fins, sometimes caudal fin • Lay egg case (mermaid’s purse) • Rays • Narrow tail without fins, with spines
Class Chondrichthyes Subclass Elasmobranchii Caudal fin
Chondrichthyes Anatomy Rostrum
Chondrichthyes Reproduction • Internal fertilization • Males have claspers between pelvic fins • Reproductive modes • Oviparous • Fertilized egg is laid • Ovoviviparous • Egg develops within female and living young are born • No placenta or placental structures • Viviparous • Embryos develop within female and living young are born • Some placenta-like structures of maternal origin
Group Osteichthyes – bony fish • Class Actinopterygii – ray-finned fish • subclass Neopterygia • subclass Chondrostei • Class Sarcopterygii – fleshy-finned fish seahorse flying fish grouper coelacanth lungfish
Primitive Bony Fish – Subclass Chondrostei • Nonteleost bony fish • Heterocercal tail • Ganoid scales • Lungs Gar
Subclass Neopterygia – • Teleost • Swim bladder • Two dorsal fins • Homocercal tail Bass Tuna Salmon Walleye