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Part 1. Where does it start?. Early Chordates, Craniate and vertebrate origins. Phylum Chordata. Animal Kingdom. Vertebrates over here. Chordata (animals with notochord at some stage in life cycle). Craniata (euchordates with a cranium) = Vertebrata. Gnathostomata (Craniata with jaws).
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Part 1 Where does it start? Early Chordates, Craniate and vertebrate origins
Animal Kingdom Vertebrates over here
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 Phylum Chordata
Phylum Echinodermata Phylum Chordata - Origins Phylum Hemichordata
Carpoids Fossil echinoderms …..a link between non-chordates and chordates?
Deuterostomia Ambulacraria Hemichordata Chaetognatha Echinodermata Xenoturbellida Chordata Enteropneusta Xenoturbella Pterobranchia Loss of gill slits Pentaradiality Postanal tail Buccal diverticulum Endoskeleton of stereom ossicles Hooded circlet of spines around mouth Mesocoelomic ducts 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
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 5 traits define all chordates
Protochordata Agnatha Urochordata (tunicates) Petromyzontida (lampreys) Myxini (hagfishes) Cephalochordata (lancelets) 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
Chordate Traits Endostyle
Adaptive significance Gill arches Vertebral Column Complex central Nervous system
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 Phylum Chordata
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 “Protochordates”
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 Craniates
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 Vertebrates
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 “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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 “Fishes”: 6 distinct lineages
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) Reptilia Protochordata Agnatha Osteichthyes (bony fishes) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 Amphibians
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) Amniotes Reptilia Protochordata Agnatha Osteichthyes (bony fishes) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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 Mammals (Synapsida)
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) Skull with upper and lower temporal fenestra, Beta-keratin n 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 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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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
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) Actinopterygii (ray-finned fishes) Urochordata (tunicates) Petromyzontida (lampreys) Mammalia (mammals) Testudines (turtles) Lepidosauria (lizards, snakes) Aves (birds) Sarcopterygii (lungfishes, coelacanths) Amphibia Crocodilia Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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
“Protochordates” Not craniates – but the same phylum
Subphylum Cephalochordata lancetes, amphioxus
notochord nerve cord perforated pharynx endostyle post-anal tail
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 Myxini (hagfishes) Cephalochordata (lancelets) Hair, mammary glands Chondrichthyes (sharks, rays, chimaeras) 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
Vertebrata Craniata
Craniate innovations Cranium
Craniate innovations Tripartite brain Forebrain Midbrain Hindbrain
Craniate innovations Complex Cranial Sense organs Olfaction Vision Hearing (otic)
Craniate innovations Inner ear with at least one semicircular canal
Craniate innovations ? Unique embryonic tissues neural crest cells ectodermal placodes
Acraniate Chordate Craniate
Very early craniates (probably) †Myllokunmingia † Haikouichthys †others
Very early craniates (probably) †Myllokunmingia † Haikouichthys †others
Relationships under debate †Myllokunmingia † Haikouichthys
Most primitive (living) craniate Hagfishes
Vertebrata Craniata
Vertebrata Vertebrates
Vertebrate innovations Vertebrae
Vertebrate innovations Inner ear with at least two semicircular canals
Vertebrate innovations All sorts of new physiology
Most primitive living vertebrate Lampreys