New discovery on taxonomy of toxic microalgae
Research results on O. siamensis with specimens collected in Vietnam are also recorded on the Algaebase world microalgae website, www.algaebase.org/search/species/detail/?species_id=54506
Ostreopsis siamensis was first discovered by the Danish scientist Johannes Schmidt in the southern part of Koh Chang, Gulf of Thailand, in 1901, and 80 years later, Fukuyo (1981) detailed the species found in the Ryukyu Islands (Japan). Many years later, scientists around the world have identified about 11 species of the genus Ostreopsis. The species have almost the same phenotype and are quite similar in number of shell plates, so identification must be based on both morphological and genetic features. Some phenotypes obtained from nature and in culture with anomalous cell transformation did not match those described by Schmidt (1901).
The question is: “Will the species of O. siamensis change its morphology after more than 100 years with changes in the environment and global warming; Is this species real or does it no longer exist in the marine environment?” Scientists have not found standard specimens in contemporary museums, and it is this fact that has created a lot of controversy in taxonomy.
Figure A-H. Ostreopsis siamensis in Vietnamese waters, recognized as an epitype, Nguyen-Ngoc L. et al. 2021 is kept in the Oceanographic Museum; Botanical Museum (Institute of Tropical Biology, Ho Chi Minh City) and Natural History Museum of Denmark
Based on morphological and genetic evidence of specimens collected from Con Dao, coastal My Hoa (Phan Rang, Ninh Thuan), Nha Trang Bay, Ghenh Rang (Quy Nhon); The article proved that the specimen in Vietnam was completely similar to the original description of Schmidt (1901) and had the same genotype. According to taxonomy, for accuracy and reliability, specimens must be found in the area where the species was first discovered. This paper has identified specimens from Phu Quoc waters that share the same morphological and genetic characteristics with specimens from Con Dao, My Hoa, Nha Trang and Quy Nhon. Although there is a slight difference in cell shape under natural conditions and some morphological changes in culture conditions, the results of phylogenetic plant analysis show that all Vietnamese specimens in this study were all O. siamensis.
This research result has resolved the controversy of taxonomists around the world for more than a century. Together with published works on toxic microalgae, red tide forecasting and bio-oceanography, climate change, this scientific publication has contributed to affirming the capacity of microalgae bio-ecological research of Vietnam in general and Institute of Oceanography (Vietnam Academy of Science and Technology) in particular.
Translated by Phuong Ha
Link to Vietnamese version
