Uncovering cryptic diversity and biogeography of the poorly known cryptophyte genus Proteomonas Hill & Wetherbee.
Supervisor: Aitor Laza (UPV/EHU)
Proteomonas sulcata is described as a single-species genus until date. It was first described more than three decades ago. This cryptophyte was identified to represent two life forms (haplomorph and diplomorph). In this study Proteomonas sulcata-like strains together with strains showing some morphological differences were analysed to gain insight into taxonomy and distribution of this poorly known genus. We propose two morphospecies within the Proteomonas genus both represented by the haplomorph form. They have been characterised for morphological traits based on light microscopy, scanning electron microscopy and type of phycobiliprotein. Both these morphospecies have been distinguished by morphological as well as molecular methods. The three plastidial markers (rbcl, psbA and partial 23S rRNA) used here reveal different clades for the morphospecies. The two morphospecies each contain strains from different geographical location, and it is suggested that they occupy different niches (benthic and pelagic). The two morphospecies here are referred to as ‘Sulcata’ and ‘Acuta’morphotypes. The Sulcata morphotype appears to be more varied terms in terms phylogeography, what supports the hypothesis of it being benthic and thus with smaller dispersal capacity. On the other side, acuta morphotype appears to show less variation in phylogeography, supporting it to be a pelagic form, and thus with higher dispersal capacity. The two lineages within the sulcata morphotype are in accordance with their geographical location i.e. Atlantic Temperate and Atlantic Tropical which are different from the lineage of authentic P. sulcata from the Pacific, suggesting that the Sulcata morphotype strains from this study are different than the authentic P. sulcata.

Keywords: cryptophyte, proteomonas, morphospecies, sulcata, acuta, phylogeography, genetic distance