Marine planktonic dinoflagellates of the order Dinophysiales (Dinophyta) from coasts of the tropical Mexican Pacific, including two new species of the genusAmphisolenia

Abstract

Despite a recent revision of the dinoflagellates of the order Dinophysiales on Mexican coasts and a checklist of dinoflagellates from the Mexican Pacific, many records still need to be confirmed, for there are very few reliable illustrations and/or descriptions. In this paper, species composition and distribution of dinoflagellates belonging to the Dinophysiales, the product of the analysis of net phytoplankton material collected from coasts of the tropical Mexican Pacific (Jalisco to Chiapas) are presented. The material has been studied using light microscopy, although a few species were also studied by scanning electron microscopy (SEM). Forty-one species from five genera were identified, with two new records annotated for the Mexican Pacific:Amphisolenia thrinaxandMetaphalacroma skogsbergii, and two new species of the genusAmphisolenia,Amphisolenia fusiformissp. nov. andAmphisolenia michoacanasp. nov. Illustrations, dimensions and distribution data are provided for each species, and descriptions of the new species are also given.Amphisolenia palmata,A. rectangulata,A. truncata,Dinophysis apicata,D. hindmarchii,Histioneis biremis,H. crateriformis,H. pulchra,Ornithocercus cristatus,O. heteroporoidesandO. orbiculatusare illustrated for the first time in the waters of the Mexican Pacific. The number of species found in this study is relatively low. The speciesDinophysis norvegicaandD. sacculus, reported in previous papers, do not seem to occur in Mexican waters, as their distribution is rather limited to the Mediterranean Sea and the North Atlantic, respectively. Finally, the identity of certain species ofDinophysisand the nature of the new species described here are discussed.