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




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

Characteristics

 

Chondrichthyes (Cartilaginous fish)

Osteichthyes (Bony fish)

 

Habitat Mainly marine Marine as well as freshwater
Symmetry Usually dorsoventrally flattened Usually bilateral symmetry
Endo-skeleton Cartilaginous Mostly bony
Caudal fin Heterocrecal Heterocercal or diphyceral
Pelvic fin Usually posterior. Mostly anterior, occasionally posterior.
Mouth Large, crescent shaped on the ventral side of the head Variable 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
Cloaca A true cloaca is present  

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

Stomach Typically J-shaped Shape variable. Absent in some.
Intestine Short with spiral valve in lumen Long with no spiral valve
Liver Usually has two lobes Usually 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
Retina Lacks cone cell a pair of cone cells preesnt
Eggs A small number of large eggs with plenty of yolk A large number of small eggs with little yolk
Fertilisation Internal Usually external
Development internally. externally.
Examples Scolidon, Electric ray, string ray, Sharks, Labeo, catla, Hilsa, Wallago, Hippocampus

 

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