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Brachiopods (from Latin bracchium, arm + New Latin -poda, foot) make up one of the major animal phyla, Brachiopoda. Also known as lamp shells, they are sessile, two-shelled, marine animals that somewhat resemble "clams" externally but are quite different internally. Unlike bivalves, which have a left shell and a right shell, brachiopods are always bilaterally symmetric, although the top and bottom shells usually differ in shape. The shells may be either phosphatic or calcaerous. Some fossil forms also had elaborate spines. Read more about ... |
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Ammonites are an extinct group of marine animals (subclass Ammonoidea) in the phylum Mollusca and class Cephalopoda. Their fossil shells have variable forms: often flat spirals but there are some rarer non-spiraled forms, called heteromorphs. The spiral forms are responsible for the animals name as they somewhat resemble a tightly coiled ram's horn (the god Ammon was commonly depicted as a man with ram's horns) The Ammonites became extinct at the end of the Cretaceous. Read more about ... |
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Belemnites (or belemnoids) are an extinct group of marine cephalopod, very similar in many ways to the modern squid and closely related to the modern cuttlefish. Like them, the belemnites possessed an ink sac and ten arms (or tentacles). Belemnites were numerous during the Jurassic and Cretaceous periods, and their fossils are abundant in Mesozoic marine rocks. The belemnites became extinct at the end of the Cretaceous period. Read more about ... |
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