Non-coralline crustose algae associated with maerl beds in Portugal: a reappraisal of their diversity in the Atlantic Iberian beds

Abstract

Abstract In recent years (2007–2009), the distribution and associated flora of maerl beds in southern Portugal (Algarve) were investigated by dredging and SCUBA diving (12–30 m depth). The present work provides the first data on the non-coralline crustose flora associated with maerl beds in Portugal. Peyssonnelia bornetii is a new record for Atlantic European coasts, and new records for Portugal are “Rhododiscus pulcherrimus” (sporophyte phase of Atractophora hypnoides), Contarinia peyssonneliaeformis, “Cruoria rosea” (sporophyte phase of Halarachnion ligulatum), Peyssonnelia armorica, and “Aglaozonia chilosa” (sporophyte phase of Cutleria chilosa). In addition, the records of three other species (Hildenbrandia crouaniorum, Peyssonnelia dubyi, and Peyssonnelia harveyana) completed the distribution gap between the North Iberian Peninsula and the Macaronesian region. The female and carposporangial structures of C. peyssonneliaeformis and P. bornetii are described for the first time. The diversity and species composition observed are compared with previous studies from maerl beds in the northwestern Iberian Peninsula (Galicia) and neighboring areas in the Atlantic Ocean and Mediterranean Sea. In order to facilitate and promote further studies of the crustose flora of subtidal habitats along European coasts, an identification key is provided for the 26 crustose taxa associated with maerl and gravel beds of the Atlantic coast of the Iberian Peninsula.