Silurian trace fossils from Africa and South America mapping a trans-Gondwanan seaway

By their complex morphologies, predominantly benthic life styles, and limited larval dispersal, trilobites are particularly suited for stratigraphic correlation and palaeogeographic reconstructions. This is also true for their burrows (Cruziana) found in otherwise non-fossiliferous sandstones. So far, an Early Silurian age of the Balc arce Quartzite (Prov. de Buenos Aires, Argentina) has been inferred by relais correlation with African sections. The discovery of a very distinctive South American ichnospecies (Cruziana bonariensis) in the Akakus Sandstone (Libya), in Paraguay, and in Jujuy (NW Argentina) as well as a cruzianaeform version of Cruziana acacensis in Brazil, Paraguay and Argentina not only corroborates this correlation. It also supports the existence of a transcontinental seaway that allowed direct faunal exchange between the northern and southern coasts of Gondwana.