Chordata Part 1

What are the 5 chordate hallmarks?

1. Notochord

2. Dorsal tubular nerve cord

3. Pharyngeal pouches and gill slits

4. Endostyle or thyroid gland

5. postanal tail

heterocercal tail

homocercal tail

diphycercal tail

What are the subphyla we learned about?

• Subphylum Urochordata

• Subphylum Cephalochordata

• Subphylum Vertebrata

Subphylum Urochordata

• tunicates or sea squirt

chordate characters in larvae forms only

sessile adults w/out notochord and nerve cord

Subphylum Cephalochordata

• lancelets

all characteristics throughout whole life

Subphylum Vertebrata

notochord replaced by vertebrae surrounding nerve cord

enlarged brain in cranium

What are the 5 classes of Subphylum Vertebrata that we learned about?

• Class Petromyzontida

• Class Myxini

• Class Chondrichthyes

• Class Actinopterygii

• Class Sarcopterygii

Class Petromyzontida

• lampreys

buccal funnel, invasive, ammocoetae larvae

Class Myxini

• hagfishes

no buccal funnel

Class Chondrichthyes

• cartilaginous fishes (charks, skates, rays)

heterocercal tail & placoid scales

no operculum or swim bladder

Class Actinopterygii

• bony fishes

homocercal tail, ctenoid scales

Class Sarcopterygii

• lobe-finned fishes

diphycercal tail, bones for fins

placoid scales

ctenoid scales

tunicate larvae

ammocetae larva cross section

ammocoetae larvae lamprey

fish scale

amphioxus lancelet

amphioxus lancelet cross section