
Fifty eight Mastogloia species were found in samples collected in the sublittoral zone (1.5 - 7 m charted depth) on the coast of a North-Eastern Atlantic island (Groix Island). Most of them are usually present in tropical and subtropical waters. The objective of this study was to provide new information on the biogeography of the genus Mastogloia. In addition, the morphology of four undetermined taxa was described using LM.