English abstract
The genus Heterocapsa Stein is a relatively small armoured dinoflagellate. Because it has few differences in morphological characteristics among its species, species identification is difficult. In this study, small Heterocapsa sp. cells associated with a dense bloom of Cochlodinium polykrikoides Margalef were collected from the south-east coast of Iran. While Heterocapsa sp. was isolated, C. polykrikoides could not be isolated by single cell or serial dilution methods. Thus, a unialgal strain of Heterocapsa sp. was used for molecular analysis and species identification. In order to carry out phylogenetic analysis, rDNA was extracted and large subunit domains of D1-D3 were sequenced. Similar sequences of other geographical strains were selected from GenBank and compared with the Iranian species. The Iranian strain was aligned with Heterocapsa spp. Phylogenetic analysis of maximum likelihood and neighborjoining demonstrated that Heterocapsa sp. does not form a monophyletic group. Morphological characteristics confirmed molecular results. This is the first record of Heterocapsa isolation from Iranian coastal waters.
