Three melobesioid crustose coralline red algae from South Africa: Leptophytum acervatum (Foslie) comb. nov., L. foveatum sp. nov. and L. ferox (Foslie) comb. nov.

Abstract Three common crustose coralline algae from South Africa are attributed to the genus Leptophytum of the subfamily Melobesioideae. Leptophytum acervatum and L. foveatum are epilithic or epizoic with thin, flat thalli and deeply sunken conceptacles. They are very similar in appearance but, in addition to different vegetative and reproductive anatomical features, L. acervatum grows mainly on loose stones, L. foveatum on bedrock, tunicate tests and shells. Leptophytum ferox is mainly epilithic but also grows round worm tubes. It is one of the most common intertidal crustose coralline species in South Africa and shows great variability in form, ranging from flat to extravagantly protuberant thalli. Leptophytum acervatum agrees well with the lectotype of Lithothamnion acervatum Foslie. Leptophytum ferox corresponds with the holotypes of Lithothamnion ferox Foslie and L. falsellum f. plicata Foslie, and the lectotype of L. prolixum Foslie; its relationship to L. falsellum Heydrich is discussed. The featu...