Graptolite fossil - Tetragraptus fruticosis
Tetragraptus fruticosis, a graptolite fossil from the Lower Ordivician, Australia. Graptolites are an extinct class of animals in the Hemichordata phylum. The fossils represent the skeletal sheath of a colonial, soft-bodied marine invertebrate which was free-floating. They are an important index fossil for dating rocks from the Paleozoic Era.
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