Synapomorphies

(Urochords, Cephalocords, Vertebrates)

Notochord

Post-anal tail

Endostyle: ciliated groove, produces musous to help trap food particles

Tadpole

Enlarged branchial basket

Tunic: protective polysaccharide wall (sugar wall)

Incurrent siphon (mouth) and excurrent siphon (atriophore)

-in one end, out the other

Notochord disappears after metamorphisis

Synapomorphies of Eurochordata

(Cephalocords and Vertebrates)

Myomeres: striated muscle fibers, fluid movement

Closed circulatory system

Velum: separates pharyngeal slits from digestive tract, one way flow of water

Hepatic diverticulum: similar function to the liver-secretory absorptive and storage functions

Unique buccal apparatuses:

-buccal cirri: filters unwanted particles

-oral hood

-vestibule: contains the wheel organ

-Hatschek's pit: produces mucus to trap food particles

Sense organs for sight, hearing, and smell

Branchial apparatus with gills and visceral skeleton

Two chambered heart

Cranium

Tripartite brain: believed to be associated with sense organs

Functional kidney and liver

Non-calcified support system

Hagfish

All marine

Lack vertebrae and eyes are light/dark

Slime glands

Slime glands

Oral tentacles

Accessory hearts

Dorsal and anal fins with fin rays

Photosensory pineal gland

2 semicircular canals

Lateral line system

Neural arches

Vertebrae

Oral hood

Vertebral arches

Tidal ventilation: water enters adn exits through the gill openings in the adult

Primitive ribs

Jawed Vertebrates, Gnathostomes

(Diagram)

Chimaeras (ratfish)

pelvic claspers

cephalic claspers

scaleless skin

single gill opening

spine in dorsal fin

flattened bodies

enlarged pectoral fins used for rajiform swimming

spines in dorsal side and caudal peduncle

generally, flat teeth for crushing

some w/specialized electric organs

Similar characteristics due to shared ancestry

Modified lung

Oxygen extracted from gas bladder via rete mirabile

Lobe-finned fish

lungfish and coelacanth

Bichirs

unique dorsal spines

four instead of five gill arches

sturgeon and paddlefish

no/reduced scales

cartilaginous skeleton

heterocercal tail

homocercal tail

mobile premaxilla (suction pump feeding)

bony-tongued fishes

mobile premaxilla

Subdivision Elopomorpha

Order Anguilliformes

eels and gulpers

dorsal, tail, and anal fins are all continuous

no pelvic fins

larvae are pelagic (swimming in open ocean water column)

herrings and anchovies

dorsal fin far forward of anal fin

sawtoothed bellies

fin gill rakers

Subdivision Euteleostei

Order Characiformes

hatchetfishes, piranhas, tetras

fusiform

pharyngeal teeth

salmon and trout

anadromous

flyingfishes

pectoral fins act as wings

Pipefishes, seahorses

dermal plates, small mouths, slow to reproduce

population whose members can interbreed and produce fertile offspring

only applies to populations that we can observe breeding

two chambered heart

heart --> gills --> body --> heart -->

filaments: gas exchange

rakers: filters

arches: physical support