Cyst-theca relationships and phylogenetic positions of Peridiniales (Dinophyceae) with two anterior intercalary plates, with description of Archaeperidinium bailongense sp. nov. and Protoperidinium fuzhouense sp. nov

摘要: Summary Protoperidinium species with two anterior intercalary plates were originally classified by Jorgensen in the subgenus Archaeperidinium and assigned to sections Excentrica, Avellana Taylor, on basis of relative size extent cingulum displacement. Phylogenetic relationships among these three have not been fully explored. Recently, was reinstated as a genus, but several fitting emended description transferred formally molecular data available. In present study we examined cyst-theca relationship seven plates: four Protoperidinium Archaeperidinium, from China Sea. Partial large subunit ribosomal DNA sequences obtained single-cell polymerase chain reaction, for cyst stellatum France. Two new species, bailongense fuzhouense, described based both theca morphology, A. constrictum P. abei var. rotunda established first time. Maximum-likelihood Bayesian inference analyses revealed that P. fuzhouense nested within sensu stricto clade despite having only six postcingular plates, genus all monophyletic. Our results suggest presence/absence sulcal fin antapical horns displacement are most stable characteristics motile stages respective clades.