First record of Bryopsis nana M.J. Wynne, 2005 (Chlorophyta, Bryopsidaceae) from the Algerian coast (Southwestern Mediterranean Sea)

The green macroalga Bryopsis nana M.J.Wynne, 2005 (Bryopsidaceae, Bryopsidales, Chlorophyta) was collected during a winter survey of hard-substrate macrobenthic communities at Plage l’Ilot, Ain Benian, west of Algiers, Algeria. The specimen occurred as an epiphyte on a geniculate coralline alga on a wave-exposed rocky/vermetid platform. Identification was based on stereomicroscopic and light-microscopic examination of diagnostic morphological characters and comparison with the protologue. The Algerian material showed the diagnostic combination of a small erect thallus approximately 5 mm high, radial branching limited to a single order, pinnules concentrated at the distal end of the primary axis, a primary axis reaching 408 µm in diameter, pinnules approximately 608 µm long and 160 µm in diameter, scars of shed pinnules 40–50 µm in diameter, and very small discoid chloroplasts 3–6 µm in diameter with a single pyrenoid. Based on the literature and taxonomic databases consulted, this is the first documented occurrence of B. nana in Algeria and the Mediterranean Sea. Because the record is based on a single thallus and lacks molecular confirmation, its biogeographical significance should be interpreted cautiously.