1. The parade of the Craniates
Part 1

2. Major synapomorphies of the Craniates
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

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

5. Agnathans
Jawless
Include:
Ostracoderms
Hagfishes and lampreys

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

7. Ostracoderms

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

10. Gnathostomes Paleozoic Placoderms Chondrichthyans Teleostomes
Ostracoderms
Paleozoic
Placoderms
Chondrichthyans
Teleostomes
Acanthoidians
Ostichthyans
jaws

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

12. 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

13. Squaliformes - sharks
Lateral gill slits

14. Rajiformes – skates, rays, sawfishes
Ventral gill slits

15. Holocephalans
Upper jaw connected to braincase

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

17. 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

18. Basal Actinopterygians
Neopterygii
Ganoid scale

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

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

21. The parade of the craniates
Part 2

22. Tetrapoda