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Superclass Osteichthyes bony fishes
• Class Actinopterygii– Ray finned fishes
• Class Sarcopterygii (lobe fin fishes)– Lung fishes– Coelocanth
Class Actinopterygii
Class Actinopterygiicharacteristics
• bony dermal scales: ganoid, cycloid and ctenoid
• paired fins and gills• well developed skull
with 60 bones• Notochord; persists
in some absent in others
• Homocercal tail• bony skeleton• Operculum covering
gills- more effective respiration
Class Actinopterygiicharacteristics
• heart is 2 chambered, 4 pairs of aortic arches
• have a mesonephritic kidney
Class Actinopterygiicharacteristics
• sexes separate; fertilization is usually external;– oviparous (lay
eggs); most– some are
ovoviviparous (eggs develop in female and she gives birth to live young
Class Actinopterygiicharacteristics
• Osmoregulation– in freshwater fishes
• the fish is hyperosmotic and
• therefore the kidney is used to get rid of excess water
Class Actinopterygiicharacteristics
• Osmoregulation– in marine fishes
• the fish is hypoosmotic – have lower salt content in
blood than in sea water – so they tend to gain salt
and lose water.
Class Actinopterygiicharacteristics
• have a swim bladder; some have lost it; – swim bladder allows for
fishes to maintain themselves in water column without expending much energy
– a floatation devise
– Swim bladders probably evolved from lungs of primitive bony fishes.
Class Actinopterygiicharacteristics
• Two types of swim bladders:– The swim bladders first were attached to the digestive
system• i.e., at the esophagus by a pneumatic duct that allowed the
bladder to be filled and emptied of air.
– In advanced bony fishes this connection is lost and the swim bladder is separate from esophagus.
• They have a very specialized gland called the rete mirabilis – which is able to keep the pressure in the swimbladder stabiliz
Class Actinopterygiicharacteristics
• Two types of migration seen in fishes
– Anadromous-• migrating from salt water to freshwater to reproduce;• spend adult life in sea • ex. salmon (born in freshwater then migrate to sea when reach
adulthood migrate back to spawning grounds)
– Catadromous - • migrating from freshwater to salt water to reproduce; • spend adult life in freshwater• ex. eels (born in Sargassum Sea migrate to rivers in
Class Actinopterygiicharacteristics
Anadromous migratione.g. salmon
Anadromous migratione.g. salmon
Catadromous migratione.g. freshwater eel
Feeding in Fishes
• Carnivorous - prey on large variety of animals• Herbivorous - eat plants• Omnivorous - eat both plants and animals• Filter Feeders - able to filter water of plankton and
detritus• Scavengers - feed on decaying plants and animals
• All the above have to do with mouth morphology
Class Sarcopterygiilobe finned fishes
• Have a fleshy lobe at base of paired fins– Precursor of appendage
to support body
• Diphycercal tail• Includes
– Lungfishes– Coelocanth
• Only 7 species exit worldwide