DOI 10.1080/09670262.2020.1829078 The family Peridiniopsidaceae encompasses mainly freshwater species of the genera Peridiniopsis, Palatinus and Parvodinium. Only one benthic, marine species ‘Scrippsiella’ hexapraecingula has been attributed to this family. Here we established five strains by isolating single Parvodinium-like cells from the marine Gulf of Thailand, Hainan Island waters (China), off Manado (Indonesia) and from a freshwater reservoir in Fuzhou (China). All strains were examined with light, scanning and transmission electron microscopy, and their SSU, ITS-5.8S and partial LSU rRNA regions were sequenced. Four marine strains share a plate formula of Po, cp, X, 4′, 2a, 6′′, 6C, 4S, 5′′′, 2′′′′ and are herein attributed to a new genus Johsia as J. chumphonensis gen. et sp. nov. Its theca is characterized by an epitheca 1.5 times as long as the hypotheca in dorsal view and a 2a plate about half the size of 1a. A type B eyespot was observed in J. chumphonensis comprising two rows of lipid globules within a chloroplast with a single row of crystals overlying the eyespot. Production of spherical cysts was observed in culture. The freshwater strain shows a plate pattern of Po, cp, X, 4′, 2a, 7′′, 6C, 5S, 5′′′, 2′′′′, characterized by two unequal antapical plates and a lack of antapical spines, fitting the description of Peridinium parvulum, which was transferred to Parvodinium as P. parvulum comb. nov. In this species, a type A eyespot was observed comprising four rows of lipid globules within a chloroplast. A molecular phylogeny was inferred based on concatenated data from SSU, ITS-5.8S and partial LSU rRNA gene sequences using maximum likelihood and Bayesian inference. Our results show that Johsia is nested within the Peridiniopsidaceae and is a sister clade to Peridiniopsis borgei and the strain UTEX1948 identified as ‘Scrippsiella’ hexapraecingula with three anterior intercalary plates.
Cyst, dinoflagellate, eyespot, freshwater, immotile cell, Peridinium parvulum
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Publisher's official version | 13 | 8 Mo | ||
Tables | - | 62 Ko | ||
Supplementary figs S18, S19. Schematic drawing of Peridinium javanicum (redrawn from Bernard, 1908) and Peridinium caudatum var. morsum (redrawn from Playfair, 1919). | - | 10 Mo | ||
Supplementary figs S16, S17. Transmission electron micrographs of vegetative cells of Parvodinium parvulum strain TIO879. | - | 6 Mo | ||
Supplementary figs S10 –S 15. Light micrographs of cells of Parvodinium parvulum strain TIO879 | - | 10 Mo | ||
Supplementary fig. S9. Schematic drawing of Peridinium parvulum (redrawn from Wołoszyńska, 1930). | - | 8 Mo | ||
Supplementary figs S5 –S 8. Schematic drawings of thecal plate patterns of Johsia chumphonensis. Fig. S5. Ventral view. Fig. S6. Dorsal view. Fig. S7. Apical view. Fig. S8. Antapical view. | - | 17 Mo | ||
Supplementary figs S1 –S 4. Light and scanning electron micrographs of vegetative cells and cysts of Johsia chumphonensis strain TIO606. | - | 19 Mo | ||
Author's final draft | 46 | 1 Mo |
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