| P number: | P549489 |
|---|---|
| Caption: | Jurassic fish. |
| Description: | By the Jurassic, between 142 and 206 million years ago, two large groups of fish dominated the seas and fresh waters. These were the ray-finned fish, including Pholidophorus (top) and Lepidotes (middle), which show many similarities to modern types, and the cartilaginous fish like sharks and the ray Spathobatis (bottom). Pholidophorus was a herring-like fish which resembled modern fish in many ways, although its body was covered with heavy scales and its backbone was less bony compared to modern fish. It was a successful predator with large eyes, flexible jaws and small teeth. Lepidotes was amongst a number of fish that had evolved a shortened upper jaw that was separated from the cheek bones so that the mouth formed a tube into which prey could be sucked. Spathobatis is the earliest of the rays. It had a flattened body and the skeleton was made of cartilage rather than bone. It lived on the sea floor where it fed on shellfish. 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: | NERC |
| Orientation: | Landscape |
| Size: | 432.53 KB; 1000 x 804 pixels; 85 x 68 mm (print at 300 DPI); 265 x 213 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Artworks |
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