First record of P entapharsodinium ( P eridiniales, D inophyceae) in the C hina S ea, with description of P entapharsodinium dalei var. aciculiferum

Summary The dinophyte genus P entapharsodinium shares an identical plate formula with that of E nsiculifera , but lacks a spine on the first cingulum plate and a median sulcal plate ( S m). Herein we established eight strains by incubating single cysts of P entapharsodinium dalei from the C hukchi S ea, Y ellow S ea, and S outh C hina S ea. The six strains from the C hukchi S ea and Y ellow S ea fit the description of P . dalei , and they share identical internal transcribed spacer region ( ITS1 , ITS2 and 5.8S rDNA ) sequences. The two other strains ( G96 and PDFC01 ) from the S outh C hina S ea are morphologically similar to P . dalei , but they possess a spine on the anterior sulcal plate and an additional S m plate. These two strains were described as P . dalei var. aciculiferum . They share identical ITS sequences and differ from P . dalei strains PDCH01 ( Y ellow S ea) and SZN19 ( N orway origin) at 20 and 26 positions (96.40% and 95.32% similarity) respectively. Maximum‐likelihood and B ayesian inference resolved a well supported clade consisting of P . dalei and P . dalei var. aciculiferum . Our results reveal that cysts of P . dalei might comprise several morphologically, genetically, and ecologically different varieties.