Cocconeis magnoareolata Al-Handal, Riaux-Gob., R.Jahn & A.K.Wulff sp. nov and Cocconeis vrangoensis Al-Handal & Riaux-Gob. sp. nov

Adil Y. Al-Handal, Catherine Riaux-Gobin, Regine Jahn, Angela Katarina Wulff, Alison Minerovic
Two new marine species of Cocconeis (Bacillariophyceae) from the west coast of Sweden
European Journal of Taxonomy 497, 2019

Abstract
This paper is part of a project of studying benthic diatom biodiversity on marine coastal regions of Sweden with focus on rare and less known species. Two new species of Cocconeis Ehrenb. are described from Vrångö, a small island in the west coast of Sweden. Both species were found as epiphytic on the green alga Ulva intestinalis L. Cocconeis magnoareolata Al-Handal, Riaux-Gob., R.Jahn & A.K.Wulff sp. nov. is a small species not exceeding 9 µm in length and characterized by having large subquadrangular areolae on the sternum valve. Cocconeis vrangoensis Al-Handal & Riaux-Gob. sp. nov. appears similar to some taxa of the ‘Cocconeis scutellum complex’, but differs by its stria density on both valves and variable features of the areola and valvocopula ultrastructure. Detailed descriptions based on light and electron microscopy examination, a comparison with closely related taxa, as well as a description of the habitat of both species are here presented.