1. Shark Skeletal System Web Sites Read pages 16 – 20 in shark book
Shark Virtual lab
Shark Dissection Images
Read pages 16 – 20 in shark book

2. Endoskeleton Provides support and protection for the softer body parts
Fundamental system on which the body is built
Skeletal bones
Endochondrial bone
Dermal / membrane bones
Not cartilage
solid bone replaces earlier embryological cartilage
our arm and leg bones

3. Squalus acanthius The Skeletal System
Axial Skeleton
Vertebrates
skull
vertebral column
rib cage

4. Axial Skeleton CHONDROCRANIUM Shark skull Divided into: Neurocranium
anterior and more dorsal part of skull
protects brain and sense organs
rostrum
nares
orbits
otic capsules
- inner ears

5. Notochord
Along the mid ventral line there is a white strand of calcified cartilage
This indicates the position of the notochord

6. Axial Skeleton SPLANCHNOCRANIUM
ventral and posterior to the neurocranium
also called visceral cranium
skeletal visceral arches form the jaws and supports the gill arches

7. Visceral Arches Supports the mouth and gills
Squalus acnathius has only seven
Mandibular Arch
modified to form the upper and lower jaws
Meckel’s cartilage
Forms the lower jaw
1st visceral arch
Hyoid Arch
2nd visceral arch
provides primary support for the jaws and is attached to them by ligaments
supports tongue

8. Gill Arches The last 5 visceral arches (3-7) Support the Gill Elements
“U” shaped, multi-jointed
Gill lamellae
surfaces upon which gas exchange takes place
Gill Rakers
prevent food from leaving the mouth and pharnyx through the gill slits

9. Shark Respiratory

10. Vertebral Column and Ribs
Tail Vertebrae
Centrum
central portion
appears white
calcified
not bone like
provides strength to vertebral column
Consists of
Notochord
passes through the center

11. Dorsal Arch
Neural Arch
Spinal chord passes through the vertebral canal
Ventral Arch
Hemal Arch
Contains the Hemal Canal through which passes the caudal artery and vein

13. Trunk Vertebrae
similar to that of tail vertebrae
lacks the hemal arches
Appendicular Skeleton
Refers to the cartilages of the pectoral and pelvic girdles
Pectoral Girdle
“U” shaped structure
encircles the ventral side of the trunk
consists of a median ventral Caracoid Bar
Pectoral Fins
3 basal fin cartilages which articulate with the girdle

14. Pelvic Girdle
composed of a single transverse rod of cartilage
puboischaic bar
Pelvic Fins
in male sharks there is a highly modified radial cartilage that forms the clasper

15. Dorsal Fins
similar in structure to pectoral and pelvic fins
larger basal cartilages are proximal to the vertebral column
smaller radial cartilages are more distal
Caudal Fins
end of the vertebral column turns upward into the dorsal part of the caudal fin
termed heterocercal

17. Shark Systems Labeled