Comparative Anatomy of Vertebrates Phylogeny

What defines chordata?

notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail

What defines urochordata?

marine invertebrate chordates, chordate traits mainly in larval stage

What defines cephalochordata?

notochord extends past nerve cord, small fish-like invertebrates

What defines craniata?

chordates with a skull

What defines vertebrata?

craniates with vertebrae

What defines “agnatha”?

jawless vertebrates

What defines cyclostomes?

living jawless vertebrates(ex: hagfish, lamprey)

What defines conodonta?

extinct jawless vertebrates

What defines “ostracoderms”?

extinct armored jawless fishes

What defines gnathostomata?

vertebrates with jaws

What defines placoderm?

extinct armored jawed fishes

What defines chondrichthyes?

cartilaginous fishes

What defines “osteichthyes”?

bony fishes

What defines actinopterygii?

ray-finned fishes

What defines sarcopterygii?

lobe-finned fishes

What defines actinistia?

ancient lobe-finned fishes, includes the living coelancanths

What defines dipnoi?

lungfishes

What defines crossopterygii?

extinct lobe-finned fishes, likely these became tetrapods

What defines tetrapoda?

vertebrates with limb-bearing digits

What defines “amphibia”?

early non-amniote tetrapods

What defines “labyrinthodonts?”

extinct early tetrapods, complex folded teeth

What defines lissamphibia?

living amphibians

What defines salientia(anura)?

frogs and toads

What defines urodela(caudata)?

salamanders

What defines gymnophiona(caecilia)?

limbless burrowing amphibians

What defines amniota?

tetrapods with an amniotic egg(doesn’t need to be in water)

What defines sauropsida?

reptiles and birds

What defines “reptiles”?

non-avian sauropsids

What defines testudines(chelonia)?

turtles(have a shell formed by ribs and vertebrae)

What defines squamata?

lizards, snakes

What defines archosauria?

crocodiles, dinosaurs, birds

What defines crurotarsi?

crocodilian archosaurs

What defines crocodylia?

crocs and gators

What defines dinosauria?

extinct dinos

What defines aves?

birds

What defines synapsida?

amniotes with a single temporal skull opening

What defines pelycosauria?

early synapsids

What defines therapsida?

advanced synapsids, almost mammals

What defines mammalia?

hair, mammary glands, 3 middle ear bones

What defines monotremata?

egg-laying mammals

What defines theria?

live-birthing mammals

What defines marsupialia?

pouched mammals

What defines eutheria?

placenta-forming mammals