Amphora acuta Gregory (1857: 524)

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 acuta Gregory (1857: 524) ( Fig. 67 )

References: Wachnicka & Gaiser 2007, p. 410, fig. 80, Levkov 2009, pl. 80, figs 1–5.

Features: Length 110–150 μm, width 12–18 μm, striae 14–16 in 10 μm.

Description: Valves semi-elliptical with acutely rounded apices. Dorsal margin arcuate, ventral margin straight or weakly concave. Raphe close to ventral margin. Axial area narrow, central area extends transversely in a form of fascia reaching dorsal margin. Ventral striae indistinct.

Remarks: This species looks similar to Amphora decussata Grunow (1877:178) but valves of the later species are narrower with more concave ventral margin and denser ventral striae.

Ecology and Distribution: A widespread marine littoral species. Not recorded previously from the Gulf. Frequent 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.