MilkfishChanos chanos

Class Osteichthyes

Actinopterygii (Ray-finned fishes)

Sarcopterygii (Lobe-finned fishes)

Membranous fins are supported by slender fin rays radiating from basal skeletal elements within the body wall

Gill slits covered by a bony operculumAir sac is usually presentInternal nares are lackingBasal ActinopterygiansNeopterygians

Actinopterygii (Ray-finned fishes)

PaleoniscoidsLarge ganoid scalesWell-ossified endoskeletonAir sacs are connected to the pharynx by an air

duct that enebles aerial respirationSturgeons and paddlefishes

Have endoskeleton is largely cartilaginousScales lack ganionSkin of paddle-fishes is naked exept for small

bony scales on tail

Actinopterygii (Ray-finned fishes)- Basal Actinopterygians

Gras and bowfinsTrunk and tail of gars are covered with ganoid scales;

trunk and tail of Amia have modern fish scalesEndoskeleton is ossifiedBrainacase (neurocranium) remains largely

cartilaginousTeleosts

“modern”Scales are in the dermis, very thin and flexibleDermal bones of the skull are thinner and more

numerous Jaws and palate are more independently maneuverable Pelvic fins are far forward

Actinopterygii (Ray-finned fishes)- Neopterygians

- Fleshy lobe at the base of their paired fins- Have internal nares that open into the

oropharyngeal cavity and retain a gas-filled air - Gill slits are covered by a bony opercullum

that grows caudad from the second pharyngeal arch

- Actinistia- coelacanths

- Rhipidistia- Dipnoans

Sarcopterygii ( lobe-finned fishes)

Lateral View

Tail fin (caudal fin)2 types of tail fin* Homocercal-  Top and bottom halves the same size.* Heterocercal-  Top half different size than bottom half.

a.       A system of canals on the sides of fishes that helps fish detect changes in pressure, vibrations and currents.b.      This incredible sense organ helps fishes to detect prey, adjust their position to the currents, and keep in position in a school.c.       They pick up vibrations from the swimming of other animals and water disturbed by sound waves, which cause changes in pressure.d.      The longer the fish’s body the longer is the lateral line and the more sensitive to the environment. The canals are not only in the skin but also in the bone or cartilage of the head.

LATERAL LINE

Ganoid Fish Scales

Found on non-teleost bony fishes

Usually diamond shaped bony scales

“Heavy armor”

Cycloid Fish scalesFound on teleost

fishes

Light, thin, & flexible

Ctenoid Fish ScalesTeleost fishesHave comblike

ridges along the exposed edge to reduce friction (drag)

Myomeres

a.       Closed circulatory system          i.      The blood is always kept in vesselsb.      Heart          i.      Only has two chambers     ii.      Blood goes from heart to gills to the rest of the body       iii.      Mammals blood goes; heart, lungs, heart, rest of body

Caviar = Sturgeon eggs