Ιχθυολογία

“jawed fishes” Class Chondrichthyes- χόνδροι Class Osteichthyes- οστά Subclass Elasmobranchii- καρχαρίες, ράτζες, μουδιάστρες Subclass Holocephali- χείμερες Class Osteichthyes- οστά Subclass Dipnoi- πνευμονόψαρα Subclass Crossopterygii- κοιλάκανθοι Subclass Actinopterygii- σύγχρονοι οστεϊχθύες

Class Chondrichthyes: (Cartilaginous Fishes) general diagnostic characters: reduced dermal armor cartilaginous endoskeleton & girdles tricuspid teeth gill slits fins: two dorsal, no anal, stiff pectorals, flexible pelvic heterocercal tail

1st Elasmobranch Radiation diagnostic characters: shark-like appearance terminal mouth; amphistylic jaw suspension unique tooth replacement claspers

2nd Elasmobranch Radiation diagnostic characters: heterodont dentition unique pectoral & pelvic fin arrangements heterocercal tail

Extant Forms Elasmobranchii [sharks (360 species) , skates & rays (456 species); appear in the Jurassic

diagnostic characters of sharks hyostylic jaw suspension & rostrum cranial kinesis- allows consumption of large food items pectoral girdle fused ventrally placoid scales lack gas bladder; liver provides buoyancy (~ 25% of body mass).

Hyostylic Jaw Suspension

sensory systems lateral line system (mechanoreceptors) ampullae of Lorenzini (detects electrical impulses) acute chemosensory tapetum lucidum internal fertilization and large female investment; oviparity, ovoviviparity, & viviparity

Placoid Scales

Shark Egg Case

diagnostic characters of skates & rays hard teeth with flat crowned plates; mostly adapted for feeding on benthic invertebrates swimming via undulations of pectoral fins stingrays (family Dasyatidae) modified placoid scales form a sting at the base of the tail manta rays (family Mobulidae) plankton feeders

Cartilaginous Skeleton

Sharks

Sting Ray

Manta Ray

Class Osteichthyes: “bony fishes” most abundant and diverse vertebrates >21,000 species bony scales (enlarged in the head region) operculum covering the gills stream-lined; laterally compressed ossified endoskeleton; secondarily lost in some species

Dipnoans subclass Dipnoi- "double breathers"; lungfishes upper jaw fused to the brain case; large, crushing tooth plates two dorsal fins paired fins

Crossopterygians dominant fresh water predators during the Devonian period rhipidistians (ancestor to amphibians) & coelacanth; Latimeria (extant)

important structural characteristics: lobed fins with elements connecting to pectoral & pelvic girdles autostylic jaw suspension- jointed braincase (jaw connects directly to the brain case) labyrinth tooth- complex folding of the enamel

Actinopterygians (ray-finned fishes) most modern bony fishes; subclass Actinopterygii important structural characteristics: ganoid scales distinctive pectoral & pelvic girdles fins attach to the body via flexible fin rays instead of a fleshy lobe branchiostegal rays no internal nares

“bony fish”

Paddlefish

Sturgeon

Fish Diversity

Smallmouth Bass

Green Sunfish

Catfish

Oklahoma Non-game Fish