Campylodiscus bicostatus W. Smith

Al-Handal, Adil Y., Thomas, Evan W. & Pennesi, Chiara, 2018, Marine benthic diatoms in the newly discovered coral reefs, off Basra coast, Southern Iraq, Phytotaxa 372 (2), pp. 111-152 : 143

Campylodiscus bicostatus W. Smith (in Roper1854: 75) ( Fig. 103 )

References: Schmidt et al. 1875, pl. 54, figs 4, 5; Hustedt 1930, fig. 874 (as C. clypeus var. bicostata Husted ); Krammer & Lange-Bertalot 1988, p. 215, pl. 178, figs 1–6.

Features: Diameter 18–26 μm, ribs 3 in 10 μm, inner transapical striae 9–10 in 10 μm.

Description: Valves nearly circular with round corners. Median part of the valve subquadrangular with round angles and two rows of striae separated by longitudinal hyaline area.

Remarks: Campylodiscus bicostatus may appear similar to smaller forms of C. fastuosus Ehrenberg (1845: 361) (see illustration by Hendey 1951, pl. 17, figs 1–6), but can be differentiated in that the inner ends of the ribs which extend from valve margin towards the center is not produced but broad and flat, as well as the two rows of transapical striae on both sides of the central area are not reaching valve upper margins.

Ecology and Distribution: Campylodiscus bicostatus is a freshwater species ( Kociolek 2005) but also found in coastal water. Not recorded previously from the Gulf. Rare in Basra corals.

Figures

FIGURES 103–110. Marine benthic diatoms in coral reefs off Basra. Fig. 103. Campylodiscus bicostatus, Fig. 104. Campylodiscus crebrecostatus, Fig. 105. Campylodiscus daemelianus, Fig. 106. Campylodiscus decorus, Fig. 107. Campylodicus imperialis, Fig. 108. Petrodictyon gemma, Fig. 109. Surirella fastuosa, Fig. 110. Campylodiscus neofastuosus.