Journal Article morphology taxonomy Alexandrium minutum Alexandrium ostenfeldii Amphidoma caudata Amphidomataceae Azadinium LC-FD LC-MS/MS Marine Toxins PCR PSP Polykrikos kofoidii RNA, Protozoan RNA, Ribosomal Research Support, Non-U.S. Gov't SEM cysts hatching dinoflagellate gamete life cycle nuclear cyclosis phylogeny plate pattern south-western Atlantic spirolides thecate dinoflagellates variability