Marine benthic diatoms in the newly discovered coral reefs, off Basra coast, Southern Iraq Author Al-Handal, Adil Y. Department of Biological and Environmental Sciences, University of Gothenburg, Sweden Author Thomas, Evan W. Biology Department, Waubonsee Community College, Sugar Grove, Illinois, USA Author Pennesi, Chiara Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italia text Phytotaxa 2018 2018-10-12 372 2 111 152 http://dx.doi.org/10.11646/phytotaxa.372.2.1 journal article 10.11646/phytotaxa.372.2.1 1179-3163 13728822 Actinocyclus curvatulus Janisch in Schmidt et al. (1878: pl. 57:31) ( Fig. 11 ) References : Schmidt et al. 1878, pl. 57, fig. 31; Hustedt, 1930 , fig. 307; Witkowski et al. , 2000 , p. 20, pl. 6, fig. 2. Features : Diameter 40–65 μm. Description : Valves circular and concave with rounded areolae decrease in size towards valve margin. Small pseudonodulus are visible near the valve margin. Remarks : This species can be distinguished by the distinctly curved rows of areolae which decrease in size towards the margin and the marginal processes located at the end of each row (internal side of the valve). Marginal pseudonodulus may become indistinguishable. Areolae 6–8 in 10 μm near the center and 10–18 in 10 μm near the margin. Marginal process 10–12 in the observed specimens which is less than those reported elsewhere (12–18). Ecology and Distribution : Widely distributed species, previously recorded from the Gulf ( Simonsen 1974 , Al-Yamani & Saburova 2011). Frequent in Basra corals.