Marine epibenthic dinoflagellates from Malaysia‐a study of live cultures and preserved samples based on light and scanning electron microscopy

Abstract

Marine epibenthic dinoflagellates have been collected from macroalgae, dead corals, seagrasses and sand in Malaysia and identified using light microscopy, including epifluorescence microscopy, and scanning electron microscopy. Examination of 62 samples revealed that Malaysia has rich diversity of benthic dinoflagellates, with 24 species representing 9 genera. Of these species, 8 were shown to be potentially toxic using the Anemia bioassay test i.e. Prorocentrum arenarium, P. lima, P. concavum, P. cf. faustiae, Gambierdiscus pacificus, Ostreopsis labens, O. ovata and Coolia sp. The diversity of potentially toxic species in Malaysian waters indicates that Malaysia may encounter problems with ciguatera and/or DSP. The highest species diversity was found at Sipadan Island with a total of 18 species identified. One of these is previously undescribed (Prorocentrum sipadanensis sp. nov.). The most common species identified at all sampling sites were Prorocentrum lima and Ostreopsis ovata. Generally, the morphology of the species identified from Malaysian waters is similar to that reported in studies elsewhere. However, new features were also observed (e.g. a pyrenoid in Prorocentrum emarginatum and two different‐sized pores in Ostreopsis labens). The importance of SEM as a tool in taxonomic studies is stressed.

Morphological and genetic characterization of benthic dinoflagellates of the generaCoolia,OstreopsisandProrocentrumfrom the south-eastern Bay of Biscay

“…The smallest and roundest (L/W 1.18) strain is Dn31EHU, the one that more closely matches the dimensions of the original description of P. emarginatum (Fukuyo, 1981), which was described as being 35-36 mm long and 32 mm wide (L/W 1.11). It also matches the description of P. emarginatum from the western Indian Ocean (Hansen et al, 2001), from Greek waters (Aligizaki et al, 2009) and from Malaysia (Mohammad-Noor et al, 2006), although a pyrenoid was observed in some cells in the latter two studies. The most elongated strain is Dn32EHU (L/W 1.38), which shows a thecal surface with scarce pores without a clear radiating pattern.…”

“…Our strain lacks poroids and fits P. rhathymum for most morphological features. Cell dimensions are slightly larger than in the original description by Loeblich et al (1979) and the reports of Mohammad-Noor et al (2006) and Aligizaki et al (2009), but fit well with those given by Fukuyo (1981). The intercalary band of P. rhathymum is described as horizontally striated in Aligizaki et al (2009) and as smooth in Mohammad-Noor et al (2006), while both horizontal and transverse striations have been observed in this study.…”

“…siamensis and Prorocentrum lima were toxic to Artemia franciscana. The toxicity of both species is well documented (Murakami et al, 1982;Rhodes et al, 2000;Bravo et al, 2001;Foden et al, 2005;Ciminiello et al, 2006Ciminiello et al, , 2008Mohammad-Noor et al, 2006;Aligizaki et al, 2008aAligizaki et al, , 2009Vale et al, 2009). Differences in the toxic character of a species can be due to the presence of multiple cryptic species within a morphospecies, as reported by Richlen et al (2008) for Gambierdiscus, or because the same species of microalgae may present varying toxicity depending on physiological status, environmental conditions or even between populations in different areas (Guerrini et al, 2009).…”

“…Nascimento et al, 2005;Mohammad-Noor et al, 2006;Aligizaki et al, 2009). Great variability in cell size and shape was observed by Aligizaki et al (2009) for P. lima strains from the North Aegean coastal waters, who considered them to be members of a P. lima species complex.…”

“…Ostreopsis cf. siamensis differs from O. lenticularis in its cell dimensions and the presence of only one size of trichocyst pore (Fukuyo, 1981;Mohammad-Noor et al, 2006). Taking into account cell shape and dimensions, thecal pores and Po size in different species of the genus Ostreopsis, the local strains best fit the Mediterranean O. cf.…”