| P number: | P549583 |
|---|---|
| Caption: | Dapedium from the early Jurassic. |
| Description: | Dapedium was a primitive ray-finned fish that lived during the late Triassic and early Jurassic. Fossils have been found as far apart as England and India. Like all ray-finned actinopterygians, it had parallel bony rays supporting and stiffening the fins. In primitive types, the fins were stiff, but more advanced fish had more flexible fins (which evolved into the mobile fins in modern fish). Dapedium retained the primitive heavy scales, but in more advanced fish, smaller scales and a swim bladder evolved, improving buoyancy. Dapedium had a deep, ovoid body and required long dorsal and anal fins to stabilize it in the water. The pectoral fins on its flanks and the paired pelvic fins were quite small. This primitive ray-finned fish had heavy, enamelled scales. Its short jaws carried long, peg-like teeth that are thought to have been used to crush molluscs. Fish are cold-blooded vertebrates with a braincase, fins for swimming and gills to take oxygen from the water (although some also have lungs). They therefore differ from other aquatic creatures like invertebrate molluscs or crabs; amphibians and reptiles, which have lungs and limbs rather than gills and fins; and whales and dolphins which are warm-blooded mammals. Fish are the first vertebrates, having evolved during the early Cambrian over 500 million years ago. |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 663.42 KB; 1000 x 703 pixels; 85 x 60 mm (print at 300 DPI); 265 x 186 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Fossils |
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