First report of Biecheleriopsis adriatica in Bolinao, Northwestern Philippines and its wide distribution in Southeast Asia and adjacent waters


by: Garry A. Benico, Kazuya Takahashi, Wai Mun Lum, Aletta T. Yñiguez, Rhodora V. Azanza, Sandric Chee Yew Leong, Po Teen Lim, Mitsunori Iwataki


Morphology and phylogeny of the marine woloszynskioid dinoflagellate Biecheleriopsis adriatica, collected from Philippines, Singapore, Palau and Japan, were examined by using light and scanning electron microscopy (SEM), and molecular phylogeny based on rDNA sequences. Cells of these cultures were ovoid to spherical, measured 11.5–17.3 μm in length, with a displaced cingulum, a sigmoid sulcus and an eyespot. Cells have an elongate apical vesicle (EAV) mostly 3.1–3.8 μm in length with globular knobs up to 32, and straight lower cingular margin in the dorsal side. These morphological characters were identical to those of B. adriatica previously reported from the Adriatic Sea, China, Japan and Korea. Molecular phylogeny based on sequences of ITS and LSU rDNA revealed that the culture isolated from Bolinao, Philippines positioned in a clade with B. adriatica. Cultures isolated from Japan, Palau and Singapore had the identical morphological characters under light microscopy, and cultures investigated were positioned in B. adriatica clade in the phylogenetic tree of ITS and LSU rDNA. B. adriatica co-occurred with a bloom of Takayama sp. associated with mass mortality of farmed milkfish in May 2016 in Bolinao, Philippines. Based on existing data, this species is unlikely the culprit responsible for the massive fish kill event but the results suggest the need for further study to clarify its role in the overall dynamics of algal blooms in Bolinao. The results also show the wide distribution of B. adriatica in Southeast Asia and adjacent waters.

Keywords: Biecheleriopsis adriatica, dinoflagellate, distribution, harmful algal blooms, Southeast Asia, Suessiaceae