First record of Lemanea fucina Bory in Italy and Paralemanea catenata (Kützing) Vis & Sheath (Batrachospermaceae, Rhodophyta) in Sicily (Italy)

Freshwater red algae belonging to the family Batrachospermaceae (Rhodophyta) are poorly investigated, particularly in Italy and in Sicily, where little is known about their distribution along rivers. The present study reports, for the first time, the occurrence of Lemanea fucina Bory in Italy and Paralemanea catenata (Kützing) Vis & Sheath in Sicily. L. fucina formed stalked, highly branched thalli and was characterised by an internal structure lacking a cortex around the central axis cell, T-shaped ray cells, and spermatangial papillae arranged in circular patches at the nodes. In contrast, P. catenata showed unstalked, unbranched to pseudobranched thalli arising from a basal crust and was characterised by a central axis composed of numerous cortical filaments and radial cells arranged in two layers: a proximal layer not reaching the outer cortex and a distal Y-shaped layer attached to the cortex, with nodal spermatangial sori arranged in rings. Both species were recorded along the Alcantara River, one of the main rivers in eastern Sicily. Information on the morphological and ecological characteristics of the two species is presented.