A giant Rusophycus from the Middle Ordovician of Siberia

The trace fossil Rusophycus (Hall, 1852) is an ichnogenus usually attributed to trilobites and formed as a result of the producing organism resting, hunting or seeking protection (Osgood, 1970; Bergström, 1973). It ranges in age from Cambrian to Triassic and has been commonly reported from shallow marine and non-marine predominantly siliciclastic deposits throughout the world (Osgood, 1970; Seilacher, 2007). From the Ordovician of Siberia however it has never been reported before. The purpose of this paper is to record an extremely large specimen of the ichnogenus discovered in the Middle Ordovician Baykit Sandstone of the Siberian Platform. This specimen is the largest Rusophycus yet recorded in Russia and can be truly regarded as “giant”. The specimen is currently housed in the Paleontological Museum of the Russian Academy of Sciences in Moscow.