Superclass Osteichthyes bony fishes Class Actinopterygii Ray finned fishes Class Sarcopterygii (lobe fin fishes) Lung fishes Coelocanth

Class Actinopterygii

Class Actinopterygii characteristics bony dermal scales: ganoid, cycloid and ctenoid

Class Actinopterygii characteristics 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 Actinopterygii characteristics heart is 2 chambered, 4 pairs of aortic arches have a mesonephritic kidney

Class Actinopterygii characteristics 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 Actinopterygii characteristics Osmoregulation in freshwater fishes the fish is hyperosmotic and therefore the kidney is used to get rid of excess water

Class Actinopterygii characteristics 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 Actinopterygii characteristics 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 Actinopterygii characteristics 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 Actinopterygii characteristics 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

Anadromous migration e.g. salmon

Anadromous migration e.g. salmon

Catadromous migration e.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 Sarcopterygii lobe 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