Ancient Species -
Rayfinned Fish
The creatures we normally think of as "fish" are known as ray-finned fish because their fins are webs of skin supported by bony spines. The fins of more ancient fish, including sharks and rays, are lobes supported by cartilage.
Ray-finned fish of several types appeared in the Devonian Period (408 to 354 million years ago). By the late Permian Period (about 250 million years ago), fish were by far the dominant aquatic vertebrates.
From the Carboniferous to the Triassic Period (354 to 213 million years ago), the dominant were belonged to a group known as paleoniscoids. These were generally small fish covered in scales which superficially resembled the bony fish of today. The paleonicoids were extinct by the end of the Cretaceous Period (144 to 66.4 million years ago).
Paleonicoids were replaced by a diverse group of bony fish known as holosteans. The sole survivor of this group is the bowfin. They were dominant during the Jurassic Period (213 to 155 million years ago).
Teleosts, which are now the
dominant type of fish, first appeared late in the Triassic
Period (about 215 million years ago). They became dominant by the late Cretaceous
Period (144 to 66.4 million years ago). They are distinguished by a moveable
upper jaw and fully symmetrical fins.
Fish fossils now available (at eBay):Click on an item to view details and, if you wish, bid. |
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Nice Group 0f Micro Cretaceous Shark & Fish Teeth From Red Bed High Way 34 Texas
FOSSIL FISH DINOSAUR ERA KNIGHTIA USA #4
Fossil Coprolite Fossil Fish Age Green River Fm COP4
New Fish Lycopter Fossil Real Stone from Western Liaoning China Specimen Decor
Fossil Fish Knightia Eocaena 7.5 inch Fossil Lake Green River Wyoming #14
Fossil Fish Knightia Eocaena 7.5 inch Fossil Lake Green River Wyoming #13
Fossil Fish Knightia Eocaena 6.75 inch Fossil Lake Green River Wyoming #15
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