Achnanthidium ennediense (Compere) Compere et Van de Vijver comb. nov. (Bacillariophyceae), the true identity of Navicula ennediensis Compere from the Ennedi mountains (Republic of Chad)
Compère, Pierre; Van de Vijver, Bart
A new combination, Achnanthidium ennediense (Compère) Compère et Van de Vijver, is proposed for an African Achnanthidium species that was previously described as Navicula ennediensis Compère. The species is characterized by strictly lanceolate, usually bent valves with a radiate striation pattern, the lack of a fascia and a raphe system that places the species within the Achnanthidium minutissimum complex. The species could be confused with Achnanthidium exile (Kütz.) round et Bukht., A. eutrophilum (Lange-Bert.) Lange-Bert., A. affine (Grunow) Czarn. and two African Achnanthes species but can be separated based on its unique combination of characters. Originally described from the Ennedi Mountains in northern Chad, this species is a typical constituent of freshwater guelta habitats in mountainous massifs in the Sahara and in other parts of Africa, south of the Sahara.