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The oldest recorded fish are from the Cambrian Period. Their fossil record ranges right up to modern times with some 20 000 species of bony fish living in today's oceans, lakes, and rivers. This large number of species accounts for approximately half of all living species of vertebrates. Modern fish diversities are so high that countless numbers of species are still undescribed and unnamed.
Fish are divided into several larger groups based on gross morphological features of the skeleton. The most primitive fish are the Agnatha (jawless fish), surviving today as lamprey and hagfish. The majority of these primitive fish, that we know of, had an external bony skeleton covering the head and thoracic regions. The Placodermi also had an external bony skeleton, but they had functional jaws. Placoderm fish became extinct at the end of the Devonian period. For more information on Placoderms, refer to the Devonian Gallery.
Fish background information provided by Andrew R. Milner;
Hague luxury hotels Hanman's Fossils and Minerals
info@hanmansfossils.com http://www.hanmansfossils.com
Centriscus strigatus
Messinian Stage, Marechia River, Rimini, Italy Lycoptera sp. China Peipiaosteus pani Pani Lake, Liaoling Province, China Hipposignathus imporcitor Santa Maria, California Xiphactinus audax Smoky Hill Chalk Member of the Niobrara Formation Lycoptera sp. China
Miocene, about 5 million years old.
About 133 mm(5.5 inches) across.
Jurassic, about 115 million years old.
Matrix is about 100 mm (4 inches) across.
Jurassic, about 115 million years old.
About 200 mm(8 inches) across.
Miocene, about 5 million years old.
About 253 mm(10.5 inches) across.
Trego County, Kansas
Cretaceous, about 85 million years old.
About 1.6 m (4 feet) across.
Jurassic, about 115 million years old.
Matrix is about 100 mm (4 inches) across.
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