Actinocyclus octonarius Ehrenberg (1837: 61)

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 : 117

Actinocyclus octonarius Ehrenberg (1837: 61) ( Fig. 12 )

References: Ricard 1987, figs 35–39; Podzorski & Håkansson 1987, pl. 3, fig. 1; Witkowski et al., 2000, pl. 4, figs 2,3.

Features: Diameter 70–150 μm.

Description: Valves circular and convex with rounded areolae arranged irregularly in fascicles and decrease in size towards the margin. Large pseudonodulus occur near valve margin.

Remarks: This species can be easily distinguished by the distinct marginal psudonodulus and the fasciculate areolae which are separated by longer striae. Areolae 8–10 near valve center but become much smaller towards the margin.

Ecology and Distribution: Widely distributed marine species. Previously recorded from the Gulf ( Hendey 1970, Simonsen 1974, Al-Handal 2009; Al-Yamani & Saburova 2011). Frequent in Basra corals.

Figures

FIGURES 11–20. Marine benthic diatoms in the coral reefs off Basra. Fig. 11. Actinocyclus curvatulus, Fig. 12. Actinocyclus octonarius, Fig. 13. Lyrella abrupta, Fig. 14. Lyrella clavata, Fig. 15. Lyrella hennedyi, Fig. 16. Lyrella hennedyi var. subcarinata, Fig. 17, Lyrella spectabilis, Fig. 18. Petroneis granulata, Fig. 19. Petroneis marina, Fig. 20. Petroneis sp.