Osteicthyes

Ferran Pueyo 9B

Taxonomic group of fish with bony skeletons instead of cartiligious

Chordata i)Pisces 1) Chondricthyes/agnatha 2) Osteicthyes

Over 29,000 species ( most of fishes)

Divided into two large groups which are the ray-finned fish (majority) and the lobe-finned fish

Oldest known fossil 420 million years

Unique tooth pattern between the rows of teeth, found in fossils

Name comes from the latin word osteo which means bone

Introduction to Osteicthyes

Difference Between Osteicthyes and Chondricthyes

Osteicthyes means osseus or bony fish, Chondricthyes means cartilagenous

Difference in scales and covering of body

Chondricthyes has no air bladder or lungs

Difference in gill number

CharacteristicsSkeleton

Cranial bones

Rooted teeth

Eyeball held by four small bones (some fish have lost or changed this characteristic)

Braincase divided into anterior and posterior sections

Do not have fin spines instead have bone fin rays (lepidotrichia)

Specific characteristic that allows them to breath without swimming (operculum)

Fin limbs, related to tretapods

Characteristics (2)

Endochondral bone

Known as replacement bone

Bone ossified internally

Cartilage inside the bone is calcified and replaced with osteoplasts

Final result, bone now surrounds other bone

Very special because bone starts as cartilage but then calcifies

Liightweight, flexible interior, surrounded by denser bone

Respiratory System Breathe through gills located on either side of the pharynx

Threadlike structures called filaments

 Capillary network which creates space for exchanging oxygen and carbon dioxide

Exhale through a single opening, the gill slits, protected by a gill cover ( to keep out water from entering the lungs)

Circulatory System

 Two muscular chambers that pump the blood, atrium and ventricle. 

Atrium pumps blood into the ventricle

Bulbus arteriosus

Blood is pumped into capillary network , where the exchange of gas takes place (from aorta)

Gathers in a thin-walled sac, sinus venosus

Returns to the atrium

Sensory System Highly developed sense organs, vital for fish

Color vision, at least better than humans

Chemoreceptors that are responsible for superior senses of taste and smell

Catfish, have organs that detect weak electric currents (example)

Fish eyes are similar to those of terrestrial vertebrates like  mammals, but have a more spherical lens

Fish have pain and fear responses

Nervous system poorly developed

Digestive System

Esophagus is short and flexible , large amounts can be swallowed (layered with muscle)

Stomach muscular tube in a ‘u’ or ‘v’ shape. Gastric glands, break down food

The pyloric caeca is an adaptation for increasing the gut area; they digest food.

Pancreas

 Food absorption takes place in the intestine.

Plant-eating bony fishes generally have long intestines. Carnivorous bony fishes have shorter intestines

Life Cycle/ Expectancy Birth ; hatched from eggs (incubation)

Reproduction ; 1. SEXUAL MATURITY 2.REPRODUCTIVE BEHAVIOR

3. PARENTAL CARE

Death; Life expectancy varies greatly, usually cold-water live longer than warm.

Oldest known osteicthyes is the orange roughy  that can live up to 100 years

Diet Impossible to generalize

May be carnovour, omnivour or herbivore

Common diet:

annelid wormsmarine snailsmusselsclamssquidsinsectsbirdsamphibians,small mammalsand other fishes.

Most Known Species Sturgeons Gars Eels  Carp Herrings Anchovies Catfish Goldfishes Piranhas Seahorses Bass Cichlids Pickerel Salmon Trout Oarfish