Spirifera fossils from Williamwood, just south of Glasgow.
The Spiriferid group of brachiopods first appeared 440 million years ago in the Ordovician period. They became extinct in the Early Jurassic Period around 180 million years ago. The two Spirifera shown here belong to the genus Spirifer which only existed during the Carboniferous Period (360-290 million years ago).
Brachiopods have existed for almost 600 million years, since the Cambrian Period, although they are less abundant and fewer species exist today. Although most creatures with two opposed hinged shells (such as cockles and mussels) are known as bivalves, brachiopods are so different internally that they belong to a separate phylum (a grouping of species). They commonly live in shallow water near the seashore.
Reproduced with the permission of Glasgow City Council, Glasgow Museums
brachiopods, Cambrian Period, Early Jurassic Period, fossils, geology, Ordovician Period, Spirifer, Spirifera, Spiriferid group