Mona Hoppenrath & Nicolas Chomérat

Dinoflagellates are protists (unicellular eukaryotes) of microscopic size (most 10–100 μm). The taxonomy of dinoflagellates is dealing with morphospecies concepts, the most practical and informative approach describing and distinguishing species in the past as well as today (Hoppenrath 2017). Recent taxonomical publications contain molecular phylogenetic analyses, in many cases supporting species and genus delimitations. The number of living dinoflagellate species is estimated to be 2,000 to 2,500 assigned to approximately 300 genera, of which about 240 species in 63 genera are marine benthic taxa (Hoppenrath et al. 2023).

About 80 Prorocentrum species have been described, of which 29 are benthic. At least eight species of the genus have been shown to produce toxins. The species inhabit the interstitial spaces of marine sediments, and they live epiphytically on macroalgal surfaces, floating detritus and corals. For a more detailed review, including proposals for a unified terminology that will be used in the key, see Hoppenrath et al. (2013) or https://www.dinophyta.org/identification-keys/marine-benthic-dinoflagellates/ident-help-prorocentrum/. Some terminological additions and modifications were proposed by Tillmann et al. (2019). For detailed discussions about benthic Prorocentrum species complexes read Chomérat et al. (2019).

This key is part of identification helps and matrix keys that will be available online via the pages of the "Centre of Excellence for Dinophyte Taxonomy" (CEDiT https://www.dinophyta.org/identification-keys/marine-benthic-dinoflagellates/), as kind of addition to the book "Marine benthic dinoflagellates – their relevance for science and society" (Hoppenrath et al. 2023). You will need light and best also scanning electron microscopic observations of specimens you want to identify. This work was supported by the Friedrich Wilhelm and Elise Marx-Foundation.