Achnanthidium eutrophilum
(Lange-Bertalot) Lange-Bertalot 1999 Category: Monoraphid
BASIONYM: Achnanthes eutrophila Lange-Bertalot 1996
SYNONYM(S): Achnanthes eutrophila Lange-Bertalot
LM scalebar = 10 µm = 80 pixels.
Observations
Contributor: Marina Potapova - May 2009
Length Range: 5.4-17.8 µm
Width Range: 2.1-4.0 µm
Striae in 10 µm: 25-35 in the middle of raphe valve
Description
Valves are rhombic-elliptical to rhombic-lanceolate. The raphe valve is concave with a linear axial area. The axial area widens slightly in the middle portion of the valve. Terminal raphe fissures are straight. Central raphe endings are slightly expanded externally, and curved to opposite sides internally. The rapheless valve is convex, with a narrow linear axial area widening slightly in the middle. Striae are radiate throughout both valves, 25-35 in 10 µm. A few central striae are more distant from each other. External openings of areolae are rounded or elliptical and transapically elongated. Each stria in the middle part of the valve contains 4-5 areolae.
Original Description
Basionym: Achnanthes eutrophila
Author: Lange-Bertalot 1996
Length Range: 4–18 µm
Width Range: 3–4 µm
Striae in 10 µm: 24-27
Original Description
Schalen in Umriss regelmässig rhombisch oder rhombisch-elliptisch, bei den grösseren Exemplaren rhombisch-lanzettlisch, mit +/- breit gerundeten, niemals vorgezogen oder kopfig erscheinenden Enden. Länge 4-18 µm, Breite 3-4 µm. R-Schale: Raphe filiform. gerade bis zu den kleinen Terminalporen, niemals mit gekrümmten Terminalspalten. Axialarea schmal- bis linear-lanzettlisch, manchmal zu einer sehr kleinen Zentralarea erweitert. Meistens jedoch ist keine Zentralarea differenziert. Streiffen durchgehend radial, 24-27 in 10 µm. Die zwei mittleren sich gegenüberstehenden Streifen oder auch je zwei bis drei erschinen stärker merkiert und sind weiter entfernt gestellt als die ubrigen. RL-Schale: Zentralarea nicht ausfeprägt, Axialarea und Streifen wie auf der R-Schale.
Original Images
Cite This Page:
Potapova, M. (2009). Achnanthidium eutrophilum. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/species/Achnanthidium_eutrophilum
Species: Achnanthidium eutrophilum
Contributor: Marina Potapova
Reviewer: Sam Rushforth
Image Credit: Marina Potapova
- Striae radiate throughout both valves
- Valve rhombic
Frustule monoraphid, raphe valve concave and rapheless valve convex. Valves rhombic-elliptical to rhombic-lanceolate. Striae radiate throughout both valves, uniseriate. Two or three striae in the middle of the raphe valve are more distant from one another than other striae. Axial area narrow, only slightly widened at valve center.
Compare
Achnanthidium eutrophilum can be distinguished from A. minutissimum by its rhombic shape.
Achnanthidium minutissimum
Citations
Lange-Bertalot, H. (1999). Neue Kombinationen von taxa aus Achnanthes Bory (sensu lato). Iconographia Diatomologica 6: 276-289.
Lange-Bertalot, H. and Metzeltin, D. (1996). Indicators of oligotrophy - 800 taxa representative of three ecologically distinct lake types, Carbonate buffered - Oligodystrophic - Weakly buffered soft water. Lange-Bertalot, H. (ed.), Iconographia Diatomologica. Annotated Diatom Micrographs. Vol. 2. Ecology, Diversity, Taxonomy. Koeltz Scientific Books. Königstein, Germany, 2:390 pp.
Links & ID's
Index Nominum Algarum (INA)
California Academy of Sciences (CAS)
North American Diatom Ecological Database (NADED)
NADED ID: 1046
Autecology Discussion
Although formation of mucilagenous stalks was never observed in A. eutrophilum, this species might be able to produce stalk as other Achnanthidium species.