Critter of the DayCritter of the Day

Common name: SheepheadCommon name: Sheephead

Scientific Name:Scientific Name:Semicossyphus pulcherSemicossyphus pulcher

Phylum Chordata; Class OsteichthyesPhylum Chordata; Class Osteichthyes

Draw and note unique characteristicsDraw and note unique characteristics

CLASS OSTEICHTHYESCLASS OSTEICHTHYESBony FishBony Fish

All classes of Osteichthyes are in one of three subclasses: – Dipnoi (lung fish)– Crossopterygii – Actinopterygii

there are more than 23,500 species of bony fishes

classified based upon genetics, comparative anatomy, fossil records, molecular biology, and embryology

evolved from the jawless fish 450 million years ago

Basic Characteristics of Bony FishBasic Characteristics of Bony Fish

• skeletons are rough and bony with numerous vertebrates • usually has a homocercal tail (symmetrical tail fin

extending beyond the end of the vertebral column as in most bony fish

• most have a fusiform (round and then tapering at the ends) body type

• can fluctuate from 3 different forms of fusiform body shape:• 1. Compression• 2. Depression• 3. Elongation• common to have a laterally compressed body shape for

protection in areas of low coverage • have terminal mouth and flap covering gills

Osteichthyes Locomotion:

LOCOMOTION!!!!!

• Sequential inside-to-outside contractions along one side of the body with simultaneous relaxation along other side

• propulsion from other fins than just the body

LOCOMOTION!!!!!!

• body shape and fin location highly variable

• body design for high speed swimming

• minimize surface area exposed to fluid: sphere

• minimize cross-sectional area pencil shape

LOCOMOTION?

• minimize retarding force: teardrop (torpedo) shaped = tuna

• also inset eyes and slime reduce friction

• small scales or scaleless

Slow- fewer finsFaster- more fins- propolusion