Prorocentrum canariense sp. nov., a case of pseudo-cryptic speciation in the cosmopolitan dinoflagellate P. compressum (Prorocentrales, Dinophyceae).

The planktonic dinoflagellate Prorocentrum compressum is widespread in warm and temperate seas. A strain identified as P. cf. compressum BEA 0681B isolated from the island of Gran Canaria, NE Atlantic Ocean, showed a divergence in rDNA/ITS phylogenies with respect to P. compressum. The Canarian strain was oval, with an average length-to-width ratio of 1.35, smooth thecal surface with less than 150 thecal pores, including oblique pores, sometimes with a bifurcated opening. In contrast, P. compressum was rounder, with a length-to-width ratio < 1.2, with reticulate-foveate ornamentation and 200-300 pores per valve. We propose Prorocentrum canariense sp. nov. These species clustered as the most early-branching lineage in the clade Prorocentrum sensu stricto. Although this clade mainly contains planktonic species, the closer relatives were the benthic species P. tsawwassenense and P. elegans. Interestingly, P. compressum and P. canariense sp. nov. are widely distributed in temperate and warm seas without an apparent morphological adaptation to planktonic life. The formation of two concentric hyaline mucilaginous walls could contribute to this success. We discuss the use of Prorocentrum bidens to solve the nomenclature issue of P. compressum that was described citing a diatom as basionym.

Study of plastic pollution and its potential sources on Gran Canaria Island beaches (Canary Islands, Spain).

In order to understand the origin of plastic debris pollutants that accumulate in the Canary Islands coastline, six beaches of Gran Canaria Island were studied during different seasons to estimate the abundance and the types of two microplastics fraction sizes (0.01-1 mm and 1-5 mm) and mesoplastics fraction (5-25 mm). For the larger fraction of microplastics and mesoplastics, a high percentage of fragments and foams were found; moreover, both fractions show the same accumulation pattern in relation with the wave, wind, and current. The debris was checked for exogenous and local origins. Moreover, for the smaller fraction of microplastics, only natural, semi-synthetic, and synthetic fibres were found, showing a totally different spatial distribution from the others fractions. This result suggests a possible endogenous origin of the contamination, in relation to the type and amount of wastewater discharges and beach users.