Molecular Phylogeny of Dinoflagellate Species

Molecular phylogenetic investigations of dinoflagellate species have leveraged advancements in DNA sequencing to resolve both deep‐branching relationships and recent speciation events within this diverse lineage of unicellular eukaryotes. Ribosomal RNA genes—especially the small subunit (SSU), large subunit (LSU) and internal transcribed spacer (ITS) regions—serve as primary markers for species delimitation, while concatenated multigene and transcriptomic datasets offer enhanced support for reconstructing intergeneric relationships. These approaches have revealed widespread cryptic diversity and cases of morphological convergence, challenging traditional classifications based on thecal plate patterns or light‐microscopic traits. Environmental high‐throughput sequencing and single‐cell PCR have uncovered a far greater breadth of dinoflagellate diversity than previously documented, with direct implications for monitoring harmful algal blooms, tracking endosymbiotic lineages and managing bioinvasion risks. By integrating molecular evidence with ultrastructural and ecological data, researchers continue to refine dinoflagellate systematics, clarify character evolution and illuminate the drivers of their ecological success across marine and freshwater ecosystems.

Research from Nature Portfolio

Recent studies have described a new thecate dinoflagellate with cladopyxidoid tabulation, combining detailed plate‐pattern analysis and ultrastructure with SSU and LSU rRNA phylogenies to reassess the evolution of key plate contacts across peridinioid and gonyaulacoid lineages. This work demonstrated that features formerly regarded as specialised are in fact widespread among peridinioid taxa, prompting a revised model of character evolution within the group. By anchoring novel morphological observations to robust molecular frameworks, researchers established a precise phylogenetic placement for the new species and underscored the value of integrating classic tabulation schemes with gene‐sequence data to resolve long‐standing systematic ambiguities.

Molecular Phylogeny of Dinoflagellate Species publication trend

The graph below shows the total number of articles in molecular phylogeny of dinoflagellate species across all publications each year (not limited to Nature Index journals).

Technical terms

SSU rRNA gene: Sequence encoding the small subunit ribosomal RNA, widely used for inferring phylogenetic relationships among eukaryotes.

LSU rRNA gene: Sequence encoding the large subunit ribosomal RNA, providing complementary phylogenetic resolution to SSU data.

ITS region: Internal transcribed spacer between SSU and LSU rRNA genes, offering high variability for species‐level discrimination.

Multigene phylogeny: Phylogenetic analysis based on concatenated sequences from multiple genes, enhancing resolution of evolutionary relationships.

Operational taxonomic unit (OTU): Cluster of sequence reads used to represent presumed species or taxa in environmental sequencing studies.

Synapomorphy: Shared derived character trait used to infer common ancestry among a group of organisms.

References

1. Metagenomic Sequencing Identifies Highly Diverse Assemblages of Dinoflagellate Cysts in Sediments from Ships’ Ballast Tanks. Microorganisms (2019).
2. Evaluating the Ribosomal Internal Transcribed Spacer (ITS) as a Candidate Dinoflagellate Barcode Marker. PLOS ONE (2012).
3. Molecular phylogeny of ocelloid-bearing dinoflagellates (Warnowiaceae) as inferred from SSU and LSU rDNA sequences. BMC Ecology and Evolution (2009).
4. Fensomea setacea, gen. & sp. nov. (Cladopyxidaceae, Dinophyceae), is neither gonyaulacoid nor peridinioid as inferred from morphological and molecular data. Scientific Reports (2021).