Fish Taxonomy. KINGDOM ANIMALIA PHYLUM CHORDATA SUPERCLASS AGNATHA Class Myxini (1 order) Class Cephalaspidomorphi (1 order) SUPERCLASS GNATHOSTOMATA

Fish Taxonomy

KINGDOM ANIMALIA

PHYLUM CHORDATA

SUPERCLASS AGNATHAClass Myxini (1 order)Class Cephalaspidomorphi (1 order)

SUPERCLASS GNATHOSTOMATAClass Chondrichthyes (10 orders)Class Sarcopterygii (3 orders)Class Actinopterygii (4 orders) Division Teleostei (35-38 orders)

KINGDOM ANIMALIAPHYLUM Chordata

SUPERCLASS AgnathaClass 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 AGNATHAClass MyxiniOrder Myxiniformes (hagfishes)Class Cephalaspidomorphi Order Petromyzontiformes (lamprey)

SUPERCLASS GNATHOSTOMATAClass Chondrichthyes Subclass Holocephali Order Chimaeriformes (chimaeras) Subclass Elasmobranchii9 orders (sharks, rays, skates)Class Sarcopterygii Subclass CoelacanthimorphaOrder Coelacanthiformes (coelacanths) Subclass DipnoiOrder Ceratodontiformes (Australian lungfish)Order Lepidosireniformes (S. American, African lungfish)Class Actinopterygii - (rayfins, higher bony fishes) Subclass ChondrosteiOrder Polypteriformes (birchirs, reedfish)Order Acipenseriformes (sturgeons, paddlefishes) Subclass NeopterygiiOrder Semionotoformes (Lepisosteiformes) (gars)Order Amiiformes (bowfin) Division Teleostei35-38 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 NeopterygiiOrder Semionotoformes (Lepisosteiformes) (gars)Order Amiiformes (bowfin)

Division Teleostei35-38 orders (modern body fishes)

Bond pp. 77-87

• 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)

SUPERCLASS AGNATHA

Courtesy: tolweb.org

SUPERCLASS AGNATHAClass Myxini


• 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



• scavengers (NOT parasites)



• 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

• developed vertebrae• no paired fins; dorsal fin(s)• well developed eyes• gill pouches• two semicircular canals; single nostril

SUPERCLASS AGNATHAClass 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



• Economic importance– food source (Europe, Asia)– Great Lakes fisheries – medical research




Order Myxiniformes (hagfishes)Class Cephalaspidomorphi


SUPERCLASS GNATHOSTOMATAClass Chondrichthyes Subclass Holocephali









• jawed

• gills are slits

• paired fins

• Silurian (400 MYA)

• 4 classes– Placodermi (extinct)

– Chondrichthyes

– Sarcopterygii

– Actinopterygii (rayfins, higher bony fishes)

SUPERCLASS GNATHOSTOMATA

• Extinct• jaws first appear• gill arches first appear• paired fins• bony plates

Courtesy: http://universe-review.ca

SUPERCLASS GNATHOSTOMATAClass Placodermi

• 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.chm.bris.ac.uk

Courtesy: http://www.jaxshells.org

SUPERCLASS GNATHOSTOMATAClass Chondrichthyes


Order Myxiniformes (hagfishes)Class Cephalaspidomorphi


SUPERCLASS GNATHOSTOMATAClass Chondrichthyes Subclass Holocephali










Subclass Holocephali

Order Chimaeriformes (chimaeras)

• typically in shallow to mid-depthwater

• all marine• Cretaceous

ratfish




• 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)




elephantfish,plownose

• upper jaw/mouth fused to cranium• teeth are grinding plates

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Fish Taxonomy. KINGDOM ANIMALIA PHYLUM CHORDATA SUPERCLASS AGNATHA Class Myxini (1 order) Class Cephalaspidomorphi (1 order) SUPERCLASS GNATHOSTOMATA