Skelton & MusclesSkelton & Muscles

HagfishHagfish

No true vertebrae - sheath of cartilage surrounding notochord

Few skull bones

No true vertebrae - sheath of cartilage surrounding notochord

Few skull bones

QuickTime™ and a decompressor

are needed to see this picture.

Lamprey skeletonLamprey skeleton

Cartilaginous- limited skull- branchial basket

Chondrichthyes skeletonChondrichthyes skeleton

Cartilaginous-limited skull - 3 parts (chondrocranium, jaws, branchial cartilages)

Chondrichthyes skeletonChondrichthyes skeleton

Cartilaginous-Pectoral, pelvic girdles, fin support

Osteichthyes skeletonOsteichthyes skeleton

Osteichthyes skeletonOsteichthyes skeleton

Solid bone with complete vertebral column Simple vertebrae that lack interlocking processes One vertebra per body segment - match with

muscle masses for coordinated swimming movements

Solid bone with complete vertebral column Simple vertebrae that lack interlocking processes One vertebra per body segment - match with

muscle masses for coordinated swimming movements

Osteichthyes skeletonOsteichthyes skeleton

Vertebrae modified anteriorly for skull articulation, posteriorly for caual fin articulation

Specialized anterior vertebraeSpecialized anterior vertebrae

Posterior vertebraePosterior vertebrae

Better view of posterior vertebrae

Better view of posterior vertebrae

Trunk vertebraeTrunk vertebrae

Vertebrae in middle are trunk vertebrae of two kinds:those with ribs and those without

VertebraeVertebrae

Vertebrae without ribs

Dorsal process Neural arch with

neural spine Neural canal for

spinal cord

Vertebrae without ribs

Dorsal process Neural arch with

neural spine Neural canal for

spinal cord

VertebraeVertebrae

Ventral process Hemal arch with

hemal spine Hemal canal for

primary blood vessels (arteries, veins)

Ventral process Hemal arch with

hemal spine Hemal canal for

primary blood vessels (arteries, veins)

Spines provide supportSpines provide support

Neural and hemal spines provide support for body musculature

Especially long in laterally compressed teleost fishes

“Double comb” appearance

Neural and hemal spines provide support for body musculature

Especially long in laterally compressed teleost fishes

“Double comb” appearance

VertebraeVertebrae

Vertebrae with ribs extending ventrally and dorsally

Extend between adjacent muscle masses

Dorsal ribs well developed in pike, suckers, minnows

Vertebrae with ribs extending ventrally and dorsally

Extend between adjacent muscle masses

Dorsal ribs well developed in pike, suckers, minnows

Nice photoNice photo

Vertebrae in various fishesVertebrae in various fishes

Osteichthyes skullOsteichthyes skull

Osteichthyes skullOsteichthyes skull

>50 bones comprising 5 “groups” Neurocranium Suspensorium Jaws Opercular bones Branchiohyoid apparatus

>50 bones comprising 5 “groups” Neurocranium Suspensorium Jaws Opercular bones Branchiohyoid apparatus

NeurocraniumNeurocranium

Braincase Most of the bones Core of solid bone

around the brain plus loosely articulated bones to permit feeding (suction) and respiratory (pump) movements

Braincase Most of the bones Core of solid bone

around the brain plus loosely articulated bones to permit feeding (suction) and respiratory (pump) movements

SuspensoriumSuspensorium

Bones that connect (“suspend”) the braincase to the jaws

Bones that connect (“suspend”) the braincase to the jaws

JawsJaws

Upper and lower jaws

Change from stiff, biting mouth to flexible, sucking mouth

Maxilla (primitive), premaxilla (advanced), dentaries

Upper and lower jaws

Change from stiff, biting mouth to flexible, sucking mouth

Maxilla (primitive), premaxilla (advanced), dentaries

Opercular bonesOpercular bones

No equivalent in jawless fishes or Chondrichthyes

Primary role in respiratory pumping

Advancements (from primitive condition) small, centered on improving efficiency

No equivalent in jawless fishes or Chondrichthyes

Primary role in respiratory pumping

Advancements (from primitive condition) small, centered on improving efficiency

Branchiohyoid apparatusBranchiohyoid apparatus

Floor of the mouth, support for the gills

Includes the branchiostegal rays

Function in expansion of branchial chamber for respiration, suction feeding

Floor of the mouth, support for the gills

Includes the branchiostegal rays

Function in expansion of branchial chamber for respiration, suction feeding

Advanced fish skullAdvanced fish skull

Pectoral, pelvic girdlesPectoral, pelvic girdles

Pectoral girdlePectoral girdle

Fin rays articulate with radial bones (usually 5 radials)

Radials articulate with scapula, coracoid

These articulate with cleithrum, others

Cleithrum attached to skull

Fin rays articulate with radial bones (usually 5 radials)

Radials articulate with scapula, coracoid

These articulate with cleithrum, others

Cleithrum attached to skull

Pelvic girdlePelvic girdle

Fin rays articulate with basipterygial bone

Basipterygials either united with each other, or with cleithrum/pectoral girdle complex in more derived teleosts

Fin rays articulate with basipterygial bone

Basipterygials either united with each other, or with cleithrum/pectoral girdle complex in more derived teleosts

Dorsal, anal fin supportDorsal, anal fin support

Pterygiophores orinterspinous bones

Fish musculatureFish musculature

Segmental musclesSegmental muscles

-Right and left sidesseparated by verticalseptum-Dorsal and ventral masses separatedby horizontalseptum

Epaxial, hypaxial musclesEpaxial, hypaxial muscles

Above horizontal septum - epaxials

Below horizontal septum - hypaxials

Above horizontal septum - epaxials

Below horizontal septum - hypaxials

W-shaped myotomesW-shaped myotomes

Red vs. white musclesRed vs. white muscles

-Red - rich in blood supply - aerobic swimming (slow)-White - poor in blood supply - burst swimming (fast)-Pink - intermediate-Color may be diet-based (carotenoids/crustaceans)