Ichnology of the Phanerozoic deposits of southern Brazil

The ichnology of the Phanerozoic rocks in southern Brazil is presented and discussed herein considering its expression in the Paleozoic–Mesozoic Gondwanan units of the Paraná Basin and the Pleistocene–Holocene deposits of the southern Brazilian coastal plain. The Gondwanan units of the Paraná Basin record a complete transgressive-regressive second order depositional sequence, represented by marine deposits of the Paraná Group, glacially-infl uenced deposits of the Itararé Group, marginal-marine to marine deposits of the Guatá and Passa Dois groups and non-marine deposits of the Passa Dois, Rosário do Sul and São Bento groups. Trace fossils are present in all of these units, represented by many different ichnogenera and ichnospecies and arranged in a lot of ichnological assemblages that reflect specific paleoecological conditions in each moment of the basin filling. The southern Brazilian coastal plain deposits are better exposed in the Rio Grande do Sul littoral and are composed of four barrier-island systems that represent the transgressive-regressive cycles of the Patos Group. Its ichnological content characterizes a diverse ichnofauna, which includes marine trace fossils, with conspicuous occurrences of Ophiomorpha nodosa and Ophiomorpha puerilis, as well as its continental counterparts (mainly insect nests). This paper intends to present a review of the main ichnologic studies that have been developed in southern Brazil since the beginning of the 1980s, and to discuss some specifi c topics about paleobiology, paleoecology and paleogeography as far as ichnological analysis integrated with sedimentology and stratigraphy are concerned.