Achnanthidium gracillimum
(Meister) Lange-Bertalot in Krammer & Lange-Bertalot 2004 Category: Monoraphid
BASIONYM: Microneis gracillima Meister 1912
SYNONYM(S): Achnanthes alteragracillima Lange-Bertalot
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Marina Potapova - August 2010
Length Range: 12-21 µm
Width Range: 3.0-3.7 µm
Striae in 10 µm: 21-25 in the center valve, 36-45 at the valve ends
Description
Valves are linear-lanceolate with narrowly rostrate to subcapitate 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 slightly radiate throughout both valves. 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. Short marginal striae are often present in the middle portion of both valves. The raphe is straight, filiform. The terminal raphe fissures are sharply bent. Externally, the central raphe ends are teardrop-shaped. Internally, the central raphe ends curve to opposite sides.
Original Description
Basionym: Microneis gracillima
Author: Meister 1912
Length Range: 25-40 µm
Width Range: 3-4 µm
Striae in 10 µm: 30
Original Description
Schalen linear-lanzettlich mit gerundeten, breiten Enden, 25-40 μ lang, 3-4 μ breit. Streifen parallel, etwa 30 in 10 μ; Unterschale mit kleinem Mittelfeld.
Original Images
Cite This Page:
Potapova, M. (2010). Achnanthidium gracillimum. In Diatoms of the United States. Retrieved May 25, 2013, from http://westerndiatoms.colorado.edu/taxa/species/achnanthidium_gracillimum
Species: Achnanthidium gracillimum
Contributor: Marina Potapova
Image Credit: Marina Potapova
- Valve ends narrowly rostrate to subcapitate
- Central area absent on both valves
- Striae parallel or slightly radiate throught both valves
- Striae 21-25 in 10 μm at valve center, 36-45 in 10 μm at valve apices
Valves linear-lanceolate with narrowly rostrate or subcapitate ends. The axial area is narrow and only slightly widened in the valve center. The central area is absent. The striae are parallel or slightly radiate throughout both valves, 21-25 in 10 μm in the center valve, 36-45 in 10 μm at the valve apices.
Compare
Achnanthidium gracillimum differs from A. pyrenaicum, and A. latecephalum by narrowly rostrate or subcapitate apices. A. gracillimum differs from A. minutissimum by parallel striae throughout both valves, 21-25 in 10 μm at the valve center.
Achnanthidium latecephalum
Achnanthidium minutissimum
Achnanthidium pyrenaicum
Citations
Krammer, K. and Lange-Bertalot, H. (2004). Bacillariophyceae 4. Teil: Achnanthaceae, Kritische Erganzungen zu Navicula (Lineolatae), Gomphonema Gesamtliteraturverzeichnis Teil 1-4 [second revised edition]. In: H. Ettl et al., Suesswasserflora von Mitteleuropa. Spektrum Akademischer Verlad Heidelberg, 468 pp.
Meister, F. (1912). Die Kieselalgen der Schweiz. Beiträge zur Kryptogamenflora der Schweiz, 4/1, 1–254.
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
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: