Planothidium, ROUND & BUKHTIYAROVA, 1996

PLANOTHIDIUM ROUND & BUKHTIYAROVA

Planothidium was the second most species-rich genus in the Achnanthales off Mangareva ( Table 2), with two small taxa closely related to species first described from the Indian Ocean: P. mathurinense Riaux-Gobin & Al-Handal (in Riaux-Gobin et al. 2012a) ( Figs 31–34 View Fig ) and P. rodriguense Riaux-Gobin & Compère (ref. cit.) ( Figs 35–40 View Fig ). Planothidium delicatulum (Kützing) Round & Bukhtiyarova 1996 (see also e.g. Witkowski et al. 2000, Bahls et al. 2018, Van de Vijver et al. 2018b) was rare in several samples. Several rare and small-sized taxa, also pertaining to Planothidium , were insufficiently documented to be definitively classified ( Table 2).