Amphora arenaria Donkin (1858: 31)

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 : 133

Amphora arenaria Donkin (1858: 31) ( Fig. 68 )

References: Hendey 1964, p. 268, pl. 38, figs 1–4; Witkowski et al. 2000, p. 130, pl. 168, fig. 14.

Features: Length 102–120 μm, width 14–18 μm, striae very fine, 28–30 in 1 μm on the dorsal side.

Description: Valves linear with slightly ventrally bent rounded apices. Dorsal margin straight in the middle, becomes rounded towards apices. Ventral margin nearly straight. Raphe biarcuate, positioned in the middle of the valves, proximal endings bent ventrally. Axial area narrow, central area semi-lanceolate.

Remarks: Several observed specimens look rather similar to A. obtusa Gregory (1857: 72) , which possess almost same valve outline. Striae density may distinguish these two species where it never exceeds 20 in 10 μm in A. obtusa , mostly 10–12 in 10 μm.

Ecology and Distribution: Widely distributed marine species. Previously reported from the Gulf ( Hendey 1970). Common in Basra corals.

Figures

FIGURES 62–74. Marine benthic diatoms in coral reefs off Basra.Fig. 62. Pleurosigma diverse-striatum, Fig. 63. Pleurosigma strigosum, Figs 64, 65. Plagiotropis lepidoptera, Fig. 66. Stauroneis sp., Fig. 67. Amphora arcuata, Fig. 68. Amphora arenaria, Fig. 69. Amphora cf. commutata, Fig. 70. Amphora cingulata, Fig. 71. Halamphora coffeaeformis, Fig. 72. Halamphora costata, Figs 73,74. Amphora graeffeana.