1. Part 1 Where does it start?
Early Chordates, Craniate and vertebrate origins

2. Phylum Chordata

3. Animal Kingdom
Vertebrates over here

4. Phylum Chordata Notochord, dorsal hollow nerve cord, pharyngeal slits,
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Phylum Chordata

5. Pikaia – a very early (fossil) chordate

6. Phylum Chordata - Origins
Phylum Echinodermata
Phylum Chordata - Origins
Phylum Hemichordata

7. Carpoids …..a link between non-chordates and chordates?
Fossil echinoderms
…..a link between non-chordates and chordates?

8. Deuterostomia Ambulacraria Chaetognatha Xenoturbellida Echinodermata
Hemichordata
Chordata
Xenoturbella
Enteropneusta
Pterobranchia
Hooded circlet
of spines
around mouth
Loss of gill slits
Pentaradiality
Endoskeleton of
stereom ossicles
Buccal diverticulum
Mesocoelomic
ducts
Postanal tail
Notochord
Endostyle or
thyroid gland
Coelom tripartite
Axial complex
Unique larval
morphology
Diffuse nervous system
Unusual ciliary structure
Mouth not derived from blastopore
Enterocoely
Gill slits in pharynx
Radial determinate cleavage

9. 5 traits define all chordates
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
5 traits define all chordates

10. 5 traits define all chordates
Protochordata
Agnatha
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
5 traits define all chordates
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Slime glands,
accessory
hearts
*notochord
*dorsal hollow nerve cord
*pharyngeal slits
*postanal tail
*endostyle
Neural crest

11. Chordate Traits
Endostyle 11 11

12. Adaptive significance
Gill arches
Vertebral Column
Complex central Nervous system
Fig. 23.1 12

13. Pikaia – a very early (fossil) chordate13 13

14. Phylum Chordata Notochord, dorsal hollow nerve cord, pharyngeal slits,
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Phylum Chordata

15. Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
“Protochordates”

16. Craniates Craniata (euchordates with a cranium)
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium)
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Craniates

17. Vertebrates 2 pairs semicircular canals, vertebrae
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Vertebrates

18. “Fishes” Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
“Fishes”

19. “Fishes”: 6 distinct lineages
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
“Fishes”: 6 distinct lineages

20. Tetrapods Paired limbs used for terrestrial locomotion
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Tetrapods
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Reptilia
Actinopterygii
(ray-finned fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Aves
(birds)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Crocodilia
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Hair,
mammary
glands
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Egg with extraembryonic membranes
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Paired limbs used for terrestrial locomotion
Slime glands,
accessory
hearts
Unique supportive elements in skeleton or
girdles of appendages
Lung or swimbladder derived from gut, bony endoskeleton
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
2 pairs semicircular canals, vertebrae
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
Neural crest
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle

21. Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Amphibians

22. Amniota (tetrapods with embryos having extraembryonic membranes)
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Amniotes
Reptilia
Actinopterygii
(ray-finned fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Aves
(birds)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Crocodilia
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Hair,
mammary
glands
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Egg with extraembryonic membranes
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Paired limbs used for terrestrial locomotion
Slime glands,
accessory
hearts
Unique supportive elements in skeleton or
girdles of appendages
Lung or swimbladder derived from gut, bony endoskeleton
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
2 pairs semicircular canals, vertebrae
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
Neural crest
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle

23. Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis
Mammals (Synapsida)

24. Diapsida (“reptiles” + birds)
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin n epidermis
Diapsida (“reptiles” + birds)

25. Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis

26. Notochord, dorsal hollow nerve cord, pharyngeal slits,
Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Tetrapoda (four-limbed vertebrates)
Amniota (tetrapods with embryos having
extraembryonic membranes)
Reptilia
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Actinopterygii
(ray-finned fishes)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Mammalia
(mammals)
Lepidosauria
(lizards, snakes)
Testudines
(turtles)
Crocodilia
Aves
(birds)
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Slime glands,
accessory
hearts
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Hair,
mammary
glands
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle
Neural crest
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
2 pairs semicircular canals, vertebrae
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
Lung or swimbladder derived from gut, bony endoskeleton
Unique supportive elements in skeleton or
girdles of appendages
Paired limbs used for terrestrial locomotion
Egg with extraembryonic membranes
Skull with upper and
lower temporal fenestra,
Beta-keratin in epidermis

27. “Protochordates”
Not craniates – but the same phylum

28. Subphylum Cephalochordata
lancetes, amphioxus

29. notochord
nerve cord
perforated pharynx
endostyle
post-anal tail

31. Subphylum Craniata 31

32. Subphylum Craniata

33. Chordata (animals with notochord at some stage in life cycle)
Craniata (euchordates with a cranium) = Vertebrata
Vertebrata
Gnathostomata (Craniata with jaws)
Teleostomi (bony fishes + tetrapods)
Protochordata
Agnatha
Osteichthyes
(bony fishes)
Craniata
Actinopterygii
(ray-finned fishes)
Urochordata
(tunicates)
Petromyzontida
(lampreys)
Mammalia
(mammals)
Sarcopterygii
(lungfishes,
coelacanths)
Amphibia
Cephalochordata
(lancelets)
Myxini
(hagfishes)
Chondrichthyes
(sharks, rays,
chimaeras)
Hair,
mammary
glands
Suckerlike oral
disc, long larval
stage, 7 pairs
of gills
Heterocercal
caudal fin,
placoid scales,
cartilaginous
skeleton
Paired limbs used for terrestrial locomotion
Slime glands,
accessory
hearts
Unique supportive elements in skeleton or
girdles of appendages
Lung or swimbladder derived from gut, bony endoskeleton
Jaws, 3 pairs semicircular canals, paired appendages,
gill filaments lateral to gill support
2 pairs semicircular canals, vertebrae
Distinct head and tripartite brain, paired specialized sense organs, 1 pair
semicircular canals, glomerular kidney, ectodermal placodes
Neural crest
Notochord, dorsal hollow nerve cord, pharyngeal slits,
postanal tail, endostyle

34. Vertebrata
Craniata

35. Craniate innovations
Cranium 35

36. Craniate innovations
Tripartite brain
Forebrain
Midbrain
Hindbrain

37. Complex Cranial Sense organs
Craniate innovations
Complex Cranial Sense organs
Olfaction
Vision
Hearing (otic)

38. Inner ear with at least one semicircular canal
Craniate innovations
Inner ear with at least one semicircular canal

39. neural crest cells ectodermal placodes Unique embryonic tissues
Craniate innovations ?
Unique embryonic tissues
neural crest cells
ectodermal placodes 39

40. Acraniate Chordate
Craniate

41. Very early craniates (probably)
†Myllokunmingia † Haikouichthys †others

42. Very early craniates (probably)
†Myllokunmingia † Haikouichthys †others

43. Relationships under debate
†Myllokunmingia † Haikouichthys

44. Most primitive (living) craniate
Hagfishes

45. Vertebrata
Craniata

46. Vertebrata
Vertebrates

47. Vertebrate innovations
Vertebrae

48. Vertebrate innovations
Inner ear with at least two semicircular canals

49. All sorts of new physiology
Vertebrate innovations
All sorts of new physiology

50. Most primitive living vertebrate
Lampreys

51. Vertebrata
Vertebrates
Craniates

52. Craniates
Vertebrates