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The parade of the Craniates

The parade of the Craniates. Part 1. Developmental Neural crest Neurogenic placodes Nervous System Above Braincase (skeletal) Complex sense organs Cranial nerves Tripartite brain. Endocrine system is complex Gut Muscularization Regionalization Differentiated organs Cardiovascular

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The parade of the Craniates

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  1. The parade of the Craniates Part 1

  2. Developmental Neural crest Neurogenic placodes Nervous System Above Braincase (skeletal) Complex sense organs Cranial nerves Tripartite brain Endocrine system is complex Gut Muscularization Regionalization Differentiated organs Cardiovascular Gills Heart Hemoglobin Major synapomorphies of the Craniates

  3. Craniate phylogeny and diversity of living species Fig. 3.1

  4. Agnathans • Jawless • Include: • Ostracoderms • Hagfishes and lampreys

  5. Ostracoderms • Extinct • “Armored” – bony dermis • Middle Ordovician (maybe Cambrian) • Most lacked paired fins • Length 2-3cm to 2-2.5m • Heterocercal tail

  6. Ostracoderms

  7. Hagfish and Lampreys • Hagfish • Marine • Scavengers • Lamprey • Anadromous • Buccal funnel • Parasitic • Historically conservative anatomy (Carboniferous)

  8. Gnathostomes Ostracoderms • Paleozoic • Placoderms • Chondrichthyans • Teleostomes • Acanthoidians • Ostichthyans jaws

  9. Placoderms • Devonian (~400mya) • Paired p. and p. fins • Jointed, bony shields

  10. Chondrichthyes • Cartilaginous skeleton • Bones in scales and teeth • Elasmobranchs (sharks, skates, rays, sawfishes) • Naked gill slits (cf. bony fish operculum) • spiracle • Heterocercal tail morphology • Holocephalans (Chimaeras (ratfish)) • Scales reduced to absent • Upper jaw continuous with braincase • Fleshy operculum • Bony plates instead of teeth

  11. Squaliformes - sharks • Lateral gill slits

  12. Rajiformes – skates, rays, sawfishes • Ventral gill slits

  13. Holocephalans • Upper jaw connected to braincase

  14. Acanthodians and Osteichthyans • Acanthodians • Extinct • Hollow spines in paired fins • Bony armor

  15. Osteichthyans • The extant bony fish • Bony skeleton • Airsac • Paired appendages (fins) • Actinopterygii – ray-finned fishes • Basal actinopterygians (sturgeons, paddlefishes, Polypterus) • Neopterygians (gars, bowfins, teleost fishes) • Sarcopterygii – lobe-finned fishes • Actinistians – coelacanths • Rhipidistians – lungfishes

  16. Basal Actinopterygians Neopterygii Ganoid scale

  17. Neopterygians Teleosts (23,000 species) Bowfin Gar

  18. Sarcopterygians Tetrapods Lungfishes (Rhipidistians) Coelocanths (Actinistians)

  19. The parade of the craniates Part 2

  20. Tetrapoda

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