Fish Taxonomy
KINGDOM ANIMALIA
PHYLUM CHORDATA
SUPERCLASS AGNATHA
Class Myxini (1 order)
Class Cephalaspidomorphi (1 order)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes (10 orders)
Class Sarcopterygii (3 orders)
Class Actinopterygii (4 orders)
Division Teleostei (35-38 orders)
KINGDOM ANIMALIA
PHYLUM Chordata
SUPERCLASS Agnatha
Class Myxini (1 order)
Class Cephalaspidomorphi (1 order)
SUPERCLASS Gnathostomata
Class Chondrichthyes (10 orders)
Class Sarcopterygii (3 orders)
Class Actinopterygii (4 orders)
Division Teleostei (35-38 orders)
SUPERCLASS AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
Subclass Elasmobranchii
9 orders
(sharks, rays, skates)
Class Sarcopterygii
Subclass Coelacanthimorpha
Order Coelacanthiformes (coelacanths)
Subclass Dipnoi
Order Ceratodontiformes (Australian lungfish)
Order Lepidosireniformes (S. American, African lungfish)
Class Actinopterygii - (rayfins, higher bony fishes)
Subclass Chondrostei
Order Polypteriformes (birchirs, reedfish)
Order Acipenseriformes (sturgeons, paddlefishes)
Subclass Neopterygii
Order Semionotoformes (Lepisosteiformes) (gars)
Order Amiiformes (bowfin)
Division Teleostei
35-38 orders (modern body fishes)
SUPERCLASS AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
Subclass Elasmobranchii
9 orders (sharks, rays, skates)
Class Sarcopterygii
Subclass Coelacanthimorpha
Order Coelacanthiformes (coelacanths)
Subclass Dipnoi
Order Ceratodontiformes (lungfish)
Order Lepidosireniformes (S. American, African lungfish)
Class Actinopterygii - (rayfins, higher bony fishes)
Subclass Chondrostei
Order Polypteriformes (birchirs, reedfish)
Order Acipenseriformes (sturgeons, paddlefishes)
Subclass Neopterygii
Order Semionotoformes (Lepisosteiformes) (gars)
Order Amiiformes (bowfin)
Division Teleostei
35-38 orders (modern body fishes)
Bond pp. 77-87
SUPERCLASS AGNATHA
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Jawless - feed through sucking mouthparts
Gill openings are pores, not slits
No paired fins
Silurian/early Devonian periods (440-400 MYA)
3 classes
– Myxini (hagfishes)
– Cephalaspidimorphi (lampreys)
– Pteraspidimorphi (extinct)
Courtesy: tolweb.org
SUPERCLASS AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
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most primitive vertebrates
marine only
no larval stage (yet found)
degenerate eyes – no lens or iris
cartilaginous skeleton
no lateral line
one semicircular canal
prominent barbels
no separate dorsal fin
SUPERCLASS AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
• scavengers (NOT parasites)
SUPERCLASS AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
• structurally but not functionally hermaphroditic
(function as male OR female at a given time)
• no osmoregulation: body fluids at same salinity as ocean
• ~ 40 spp. today
• economic importance - leather and food source in Asia
SUPERCLASS AGNATHA
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
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developed vertebrae
no paired fins; dorsal fin(s)
well developed eyes
gill pouches
two semicircular canals; single nostril
SUPERCLASS AGNATHA
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
• long larval stage (ammocoetes)
• ~ 30 species - anadromous and freshwater
• parasitic forms: larvae metamorphose, reproduce as parasites
• non-parasitic forms: skip feeding stage
• non-parasitic forms (detritus-feeders) develop from parasitic
forms only in fresh water
SUPERCLASS AGNATHA
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
• Economic importance
– food source (Europe, Asia)
– Great Lakes fisheries
– medical research
SUPERCLASS
AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
Subclass Elasmobranchii
9 orders (sharks, rays, skates)
Class Sarcopterygii
Subclass Coelacanthimorpha
Order Coelacanthiformes (coelacanths)
Subclass Dipnoi
Order Ceratodontiformes (lungfish)
Order Lepidosireniformes (S. American, African lungfish)
Class Actinopterygii - (rayfins, higher bony fishes)
Subclass Chondrostei
Order Polypteriformes (birchirs, reedfish)
Order Acipenseriformes (sturgeons, paddlefishes)
Subclass Neopterygii
Order Semionotoformes (Lepisosteiformes) (gars)
Order Amiiformes (bowfin)
SUPERCLASS GNATHOSTOMATA
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jawed
gills are slits
paired fins
Silurian (400 MYA)
4 classes
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Placodermi (extinct)
Chondrichthyes
Sarcopterygii
Actinopterygii (rayfins, higher bony fishes)
SUPERCLASS GNATHOSTOMATA
Class Placodermi
• Extinct
• jaws first appear
• gill arches first appear
• paired fins
• bony plates
Courtesy: http://universe-review.ca
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
• Chimaeras, sharks, skates & rays
– cartilaginous
– teeth not fused to jaws
– ‘placental’ to oviparous reproduction
• embryos are sometimes encased
• gestation up to 2 yrs
Courtesy: http://www.jaxshells.org
Courtesy: http://www.chm.bris.ac.uk
SUPERCLASS
AGNATHA
Class Myxini
Order Myxiniformes (hagfishes)
Class Cephalaspidomorphi
Order Petromyzontiformes (lamprey)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
Subclass Elasmobranchii
9 orders (sharks, rays, skates)
Class Sarcopterygii
Subclass Coelacanthimorpha
Order Coelacanthiformes (coelacanths)
Subclass Dipnoi
Order Ceratodontiformes (lungfish)
Order Lepidosireniformes (S. American, African lungfish)
Class Actinopterygii - (rayfins, higher bony fishes)
Subclass Chondrostei
Order Polypteriformes (birchirs, reedfish)
Order Acipenseriformes (sturgeons, paddlefishes)
Subclass Neopterygii
Order Semionotoformes (Lepisosteiformes) (gars)
Order Amiiformes (bowfin)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
• typically in shallow to mid-depth
water
• all marine
• Cretaceous
ratfish
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
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gills in four pairs
spiracle absent
skin naked in adults
cloaca absent
males have pelvic intromittent organs (claspers)
two dorsal fins, first erectile with a spine and poison gland
diphycercal tail (symmetrical-tapering-whiplike)
SUPERCLASS GNATHOSTOMATA
Class Chondrichthyes
Subclass Holocephali
Order Chimaeriformes (chimaeras)
• upper jaw/mouth fused to cranium
• teeth are grinding plates
elephantfish,
plownose