Fleshy macroalgae are becoming a dominant benthic component on Caribbean coral reefs, with increased abundance and frequency across all reef zones. Over the past two decades, the brown alga Lobophora variegata has proliferated on shallow and deep reefs in Curaçao, former Netherlands Antilles. This alga provides a living substrate for a diverse epiphytic community. Here we report on Neosiphonia howei (Rhodomelaceae: Ceramiales), growing epiphytically on L. variegata over a broad depth gradient (6.5 to 40 m). Although N. howei has been reported as a typical epiphyte in shallow water, it was commonly found on L. variegata blades on the reef slope in all fertile stages. This epiphyte anchored deeply into the host tissue, suggesting hemiparasitic behaviour. The spread of L. variegata may have increased the depth-range of N. howei and the exact nature of the interaction between N. howei and its host deserves further research considering the importance of fleshy macroalgae on coral reefs.
