1. Acanthodian Body Scales
GEOL 3213

2. Many Types of Primitive Paleozoic Bony Fish
Agnathans (“jawless” fish)
Since Cambrian
Ostracoderms had bony armor plates over head
Gnathostomes
Placoderms
Chondrichthyes (“cartilaginous”)
Acanthodians (spiny)
Osteichthyes (“bony fish”)
Figure from Black (1988)

3. Five Major Categories of Fish
Agnatha
Placoderms
Chondrichthyes
Acanthodians
(Late Ord?-Late Carb.)
Osteichthyes
Figure from Levin (1999)

4. Evolutionary Relationships Among Fish
Cladistic analysis
Cladogram
Figure from Prothero (1998) 3 4 5 2 1

5. Preserved Squamation
Permian
Small body scales

6. Body Scales
Isolated acanthodian squamation on a bedding surface

7. Body scales
Isolated individual body scales in sandstone

8. Scales & Spines Acanthodian body scale (Silurian)
Acanthodian fin spine (Climatius, Silurian)
Palaeoniscid scale (Permian)
Shark tooth (Carboniferous)

9. Typical Acanthodian Skeletal Fossils
B = body scales
A & C = other scales
D & E = spines that supported fins
Devonian

10. Scales & Spines
Body scales
Spine
Devonian

11. Scales
Devonian

12. Scale
Devonian
Acanthodian scale

13. Scales
Early Miss.

14. Acanthodian Scales
Early Miss.

15. Acanthodian Scales
Early Miss.
Scales

16. Acanthodian Scales
Anterior tesserae
Late Miss.

17. Acanthodian Scales

18. Acanthodian Scales

19. End of File