Phylum Chordata
Tunicates
Amphioxus
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Phylum Chordata
Taxonomic Summary
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Phylum Chordata
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Subphylum Urochordata
Subphylum Cephalochordata
Subphylum Vertebrata
Phylum Chordata
Subphylum Urochordata
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Defining characteristics
– Notochord and nerve
cord are found only in
the larval stage
Most of the urochordates
are filter feeders
Phylum Chordata
Colonial Species
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Phylum Chordata
Nice Tunic
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Soft exoskeleton made
of cellulose with 2
external openings
Some species have
spicules and toxins in
the tunicate
Spicules
Phylum Chordata
Filter Feeding
Sexual Reproduction
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Most colonial species retain eggs and fertilization is
internal with development
The larvae are microscopic, short-lived, non-feeding,
pelagic tadpoles
Phylum Chordata
Subphylum Cephalochordata
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Defining
characteristics
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The notochord extends
beyond the nerve cord to
the anterior end of the
animal
The notochord is
contractile, formed as a
longitudinal series of
flattened discs
Phylum Chordata
A Little Ditty
It’s a long way from amphioxus,
It’s a long way to us
It’s a long way from amphioxus
To the meanest human cuss
Goodbye to tails and gill slits,
Hello: nails and hair!
It’s a long way from amphioxus
But we came from there
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Phillip H. Pope sing to the tune of “It’s a long way to Tipperary”
Phylum Chordata
Anatomy
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Phylum Chordata
Filter Feeders
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Filter feed using a
special pharynx similar
to tunicates
Slotted pharynx
supported by skeletal
bars similar to acorn
worms
Phylum Chordata
Reproduction
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Separate sexes with gonads located in the
atrial region
– Fertilization occurs in the water
– Developing young are free swimming
propelled by cilia
Phylum Chordata