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 Pleurosigma strigosum Smith (1852: 7) ( Fig. 63 ) References : Hendey 1964 , p. 246, pl. 26, fig. 7; Krammer & Lange-Bertalot 1988 , p. 294, pl. 113, figs 1,2). Features : Length 122–138 μm, width 20–26 μm, oblique striae 18–22 in 10 μm, crossing each other by an angle of 60 o or slightly larger. Description : Valves elongated, sigmoid-lanceolate in shape with protracted apices. Raphe central, sigmoid, slightly eccentric towards apices. Axial area narrow, central nodule small and rounded. Striae appear in equidistant oblique and transverse row. Oblique striae crossed each other in 60 o angle. Remarks : very similar to P. angulatum (Quekett) W. Smith (1852: 7) but can be separated by having larger striae angles and absence of terminal perpendicular striae as well as valve margins are more smoothly curved. Ecology and Distribution: A widely distributed marine species. Previously reported from the Gulf (Al-Yamani & Saburova 2011). Frequent in Basra corals.