Taxon Account

Achnanthidium parallelum J.R.Carter ex Jüttner, D.M.Williams, Ector & C.E.Wetzel; 2019; 8

Key references

Jüttner I., Wetzel C.E., Williams D.M., Ector L. 2019. Investigations of the type materials of Achnanthes parallela J.R.Carter and Achnanthes petersenii Hustedt (Bacillariophyceae) with comments on the genus Rossithidium Round & Bukhtiyarova. Botany Letters DOI: 10.1080/23818107.2019.1668297.

Morphology

Size
13.5-23.5 µm long, 3.5-5.0 µm wide (UK, type population).

Shape
Valves linear with parallel margins and broadly rounded apices.

Symmetry
Valves isopolar.

Valve
Frustules heterovalvate, raphe valve concave, rapheless valve convex. Frustules in girdle view with slightly recurved apices.

Striae
Striae more or less parallel, very slightly radiate near the centre and towards apices. 29-32 in 10 µm on raphe valve, 32 in 10 µm on rapheless valve.

Axial area
Narrow, linear axial area on both valves.

Central area
On raphe valve central area elliptical, transapically elongate and slightly irregular, bordered by 3-5 shortened striae of different length. On rapheless valve small rounded, sometimes indistinct central area.

Raphe
Raphe slit straight with round or tear-drop-shaped proximal raphe ends and terminal raphe fissures.


SEM morphology
Uniseriate striae composed of 5-8 areolae, 1-4 near apices.

Literature

References are given in chronological order.

Reference
Citation
Carter J.R. 1963. Some new diatoms from British waters. Journal of the Quekett Microscopical Club. 29(8): 199-203. Morphology; Taxonomy; Description; Type Illustration
Lange-Bertalot H., Krammer K. 1989. Achnanthes eine Monographie der Gattung mit Definition der Gattung Cocconeis und Nachträgen zu den Naviculaceae. Bibliotheca Diatomologica Vol. 18. 393 pp; 100 pls Morphology; Type Illustration; Taxonomy
Jüttner I., Wetzel C.E., Williams D.M., Ector L. 2019. Investigations of the type materials of Achnanthes parallela J.R.Carter and Achnanthes petersenii Hustedt (Bacillariophyceae) with comments on the genus Rossithidium Round & Bukhtiyarova. Botany Letters DOI: 10.1080/23818107.2019.1668297. Morphology; Taxonomy; Type Illustration;
This page should be cited as:

Jüttner I., Williams D. M., Ector L., Wetzel C. E. Achnanthidium parallelum J.R.Carter ex Jüttner, D.M.Williams, Ector & C.E.Wetzel; 2019; 8. In: Jüttner I., Bennion H., Carter C., Cox E.J., Ector L., Flower R., Jones V., Kelly M.G., Mann D.G., Sayer C., Turner J. A., Williams D.M.. Freshwater Diatom Flora of Britain and Ireland. Amgueddfa Cymru - National Museum Wales. Available online at https://naturalhistory.museumwales.ac.uk/diatoms/browsespecies.php?-recid=4628. [Accessed:  ].

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Record last modified: 27/12/2020