Fossil and Recent coralline algae bioconstructions and rhodoliths in the Brazilian shelf

In Brazil, studies on fossil crustose coralline algae (CCA) are scarce and limited to a few taxonomic accounts and to palaeoenvironmental interpretation of deposits with abundant CCA. Here, the most relevant reports on fossil and recent CCA bioconstructions and rhodolith beds are summarized from the oldest records to Holocene and living examples. The oldest CCA recorded in Brazil are from mid-dle Albian (Lower Cretaceous) deposits from the Sergipe and Potiguar basins (NE Brazil). CCA are widespread and abundant in Holocene deposits and on the modern Brazilian shelf forming extensive rhodolith beds. Boundstones of CCA are more common on the outer shelf/shelf edge. The high abundance of CCA on the Brazilian shelf is probably related to the widespread mesotrophic conditions and the relatively low input of fine-grained riverine sediment. In recent years, new molecular and morpho-anatomical studies suggest that living CCA have higher diversity and higher levels of endemicity than the ones previously reported based on morpho-anatomical taxonomy. Future studies are needed to better understand the fossil CCA occurrences along the Brazilian coast and their taxonomic and palaeoecological implications.