Molecular data unravels three freshwater peridinioids in the Baghdad Island Tourist Lake, with reporting Palatinus apiculatus (Peridiniopsidaceae, Peridiniales) as a new record for the Iraqi algal flora

In the past few decades, molecular phylogenetic approaches have been proven to be crucial techniques to precisely delimit the taxonomic position of the algal species complex. Species of dinoflagellates have been traditionally identified based on morpho-taxonomic traits, but molecular evidence accumulated over the past decades emphasized that some morphologically based descriptions need to be more accurate. This recognition led to an increasing reliance on sequencing data to delimit species identities. Our current knowledge of the diversity and distribution of dinoflagellates in Western Asian countries is still poorly known, particularly in less-studied developing countries like Iraq. Herein, the nuclear internal transcribed spacer (ITS) rRNA phylogenetic approach, as well as the morphotaxonomic features and ecological preferences, was used to refine the taxonomic assessment of three peridinioids (Peridiniales, Dinophyceae) isolated from the Baghdad Island Tourist Lake, central Iraq. As inferred from the ITS molecular phylogeny, the strain ZaFiAm50 was placed within the strongly supported Palatinus clade inside the Peridiniopsidaceae family. Considering the integrative ITS molecular and morphological traits, this species was identified as Palatinus apiculatus. This freshwater peridinioid is considered a new record for the Iraqi algal flora based on available literature. The remaining two isolates were phylogenetically belonged to the Peridiniaceae family clade, where the strain ZaFiAm80 was identified as Peridinium willei while the strain ZaFiAm10 received high branch support and resolved inside Peridinium cinctum lineage. Each species was given a short description, geographical distribution, and ecological preferences.