Two new species of Achnanthidium Kützing (Bacillariophyceae) from Kolli Hills, Eastern Ghats, India

Two new freshwater species of Achnanthidium Kutzing are described from Eastern Ghats Mountain range of Peninsular India based on light and scanning electron microscopy observations. Achnanthidium initium sp. nov. belongs to the group of Achnanthidium taxa that have terminal raphe fissures curved to opposite sides of the valve. This taxon is characterized by distinctive fascia, raphe endings extending to the valve margin, lineate distal raphe endings and 2-5 linear areola per striae. Achnanthidium linannulum sp. nov. belongs to the group of Achnanthidium taxa with terminal raphe fissures curved to the same side of the valve. This species is characterized by the presence of occluded areolae near the margin, striae orientation and the weakly bent internal distal ends of the raphe. These new species are known only from their type locality, oligotrophic Masilla Waterfalls from Kolli Hills, Eastern Ghats.