Difference between Chondrichthyes (cartilaginous fish) and Osteichthyes (bony fish)




Characteristics

 

 

Chondrichthyes (Cartilaginous fish)

 

Osteichthyes (Bony fish)

 

HabitatMainly marineMarine as well as freshwater
SymmetryUsually dorsoventrally flattenedUsually bilateral symmetry
Endo-skeletonCartilaginousMostly bony
Caudal finHeterocrecalHeterocercal or diphyceral
Pelvic finUsually posterior.Mostly anterior, occasionally posterior.
MouthLarge, crescent shaped on the ventral side of the headVariable shape and size at the tip or terminal part of the head
Gill slit 

 

Usually five pairs of gill slits which are not protected by an operculum.

Five pairs of gill slits protected by an operculum
CloacaA true cloaca is present 

 

In most bony fishes, the cloaca is absent, and the anus, urinary and genital apertures open separately.

StomachTypically J-shapedShape variable. Absent in some.
IntestineShort with spiral valve in lumenLong with no spiral valve
LiverUsually has two lobesUsually has three lobes
Brain 

 

 

Has large olfactory lobe, cerebrum and small optic lobe and cerebellum

 

Has small olfactory lobes and cerebrum and large optic lobes and cerebellum
RetinaLacks cone cella pair of cone cells preesnt
EggsA small number of large eggs with plenty of yolkA large number of small eggs with little yolk
FertilisationInternalUsually external
Developmentinternally.externally.
ExamplesScolidon, Electric ray, string ray, Sharks,Labeo, catla, Hilsa, Wallago, Hippocampus

Difference between Chondrichthyes (cartilaginous fish) and Osteichthyes (bony fish)