(Sreenivasa) Edlund 1994 Category: Monoraphid
SYNONYM(S): Achnanthes duthiei Sreenivasa
Contributor: Marina Potapova - August 2010
Length Range: 22-32 µm
Width Range: 4.5-5.2 µm
Striae in 10 µm: 14-22 in the center valve, 28-34 at the ends
Valves are linear to linear-lanceolate, with broadly capitate ends. The raphe valve is concave and the rapheless valve is convex. Both valves possess a linear axial area, which widens slightly in the middle portion of the valve. No central area is present. The striae are parallel or very slightly radiate throughout both valves. Striae density on both valves is 14-22 in 10 µm in the middle and 28-34 in 10 µm at the apices. The external openings of the areolae are transapically elongated, appearing as narrow slits. Each stria in the middle part of the valve is composed of 4-5 areolae. The raphe is straight, filiform. The terminal raphe fissures are hooked towards the same side of the valve. Externally, the central raphe ends are teardrop-shaped. Internally, the central raphe ends curve to opposite sides.
Edlund, M.B. (1994). Additions and confirmations to the algal flora of Itasca State Park. II. Diatoms from Chambers Creek. Journal of the Minnesota Academy of Science 59(1):10-21.
Ponader, K. and Potapova, M. (2007). Diatoms from the genus Achnanthidium in flowing waters of the Appalachian Mountains (North America): Ecology, distribution and taxonomic notes. Limnologica - Ecology and Management of Inland Waters 37: 227-241 . 10.1016/j.limno.2007.01.004
Sreenivasa, M.R. (1971). New fossil diatoms from Ontario. II. Achnanthes duthii sp. nov., Achnanthes undulatus sp. nov., and Neidium distincte-punctatum Hustedt var. major var. nov. Phycologia 10(1):79-82.
NADED ID: 1056