On the presence of Digenea simplex (Wulfen) C. Agardh (Rhodomelaceae, Ceramiales) in the northern Adriatic

Abstract

During a macroalgal survey along the Istrian coast in the northern Adriatic, a population of Digenea simplex was observed near the coastal town of Funtana. Additional specimens were observed and collected at four nearby locations, including areas close to Poreč, Vrsar and Rovinj. According to the available literature, the species is stated as present but is considered rare in the northern Adriatic, with no published records of the species since late 19th and early 20th century. Here we present the recently located D. simplex specimens and settlements on the western Istrian coast, relatively close to the species’ locus typicus, along with a historical overview of its presence in the northern Adriatic and beyond.