Escalera et al. (2018. Phycologia 57: 453–464) concluded that Gonyaulax hyalina and G. fragilis were the same species. Here, the morphologies of G. hyalina and G. fragilis were restudied in field samples from different parts of the World Ocean. Results showed that Escalera et al. did not observe G. fragilis, as all strains used in their study belong to one species, G. hyalina. In consequence, it is hereby proposed that the two taxa remain as separate species until further genetic studies are carried out. Additionally, the interpretation of the anterior sulcal plate as unique within gonyaulacoids is considered here inaccurate, as the plate pattern of both species is similar to other species of Gonyaulax, e.g. G. polygramma. We also show that both species may co-occur in the same sample. Their observation of an anterior intercalary plate in cultures of G. hyalina was confirmed in field samples.