Gomphonema exilissimum (Grunow) Lange-Bertalot & Reichardt; 1996; 70
Synonymy
Gomphonema parvulum var. exilissima Grunow in Van Heurck 1880
Key references
Jüttner I., Ector L., Reichardt E., Van der Vijver B., Jarlman A., Cox E.J. 2013. Gomphonema varioreduncum a new species from northern and western Europe and a re-examination of Gomphonema exilissimum. Diatom Research. 28(3-4): 303-316.
Morphology
Size
Length 20.9–39.2 µm, width 4.3–5.9 µm, length/width ratio 3.9–6.8.
Shape
Clavate, narrow elliptic-lanceolate with the widest part near the middle of the valve or closer to the head pole, in girdle view rectangular or slightly cuneate.
Symmetry
Heteropolar, valve outline symmetrical to slightly asymmetrical about the apical axis.
Striae
Central striae slightly distant from other striae which are slightly radial to parallel, stria density: 14–16 in 10 µm, 16–18 in 10 µm near poles.
Axial area
Narrow.
Central area
Small, asymmetrical formed by one short stria on the secondary side and a slightly shortened stria on the primary side, a round‘stigma’ lies close to the latter.
Raphe
Slightly undulate with slightly expanded, round central endings which are not or only slightly deflected.
SEM morphology
Internally raphe terminates in small hooks in the valve centre; striae uniseriate with mostly reniform, sometimes E- or S-shaped external areola openings.
Length 20.9–39.2 µm, width 4.3–5.9 µm, length/width ratio 3.9–6.8.
Shape
Clavate, narrow elliptic-lanceolate with the widest part near the middle of the valve or closer to the head pole, in girdle view rectangular or slightly cuneate.
Symmetry
Heteropolar, valve outline symmetrical to slightly asymmetrical about the apical axis.
Striae
Central striae slightly distant from other striae which are slightly radial to parallel, stria density: 14–16 in 10 µm, 16–18 in 10 µm near poles.
Axial area
Narrow.
Central area
Small, asymmetrical formed by one short stria on the secondary side and a slightly shortened stria on the primary side, a round‘stigma’ lies close to the latter.
Raphe
Slightly undulate with slightly expanded, round central endings which are not or only slightly deflected.
SEM morphology
Internally raphe terminates in small hooks in the valve centre; striae uniseriate with mostly reniform, sometimes E- or S-shaped external areola openings.
Literature
References are given in chronological order.
Reference |
Citation |
|---|---|
| Van Heurck H. 1880. Synopsis des Diatomées de Belgique. Atlas. Ducaju & Cie., Anvers.; 1-30 pls | Morphology; Taxonomy; Description |
| Lange-Bertalot H., Metzeltin D. 1996. Indicators of Oligotrophy. 800 taxa representative of three ecologically distinct lake types. Koenigstein, Koeltz Scientific Books. 390 pp | Morphology; Taxonomy; Illustrations |
| Jüttner I., Ector L., Reichardt E., Van der Vijver B., Jarlman A., Cox E.J. 2013. Gomphonema varioreduncum a new species from northern and western Europe and a re-examination of Gomphonema exilissimum. Diatom Research. 28(3-4): 303-316. | Morphology; Type Illustration; |
| Ress J.A., Thomas E.W., Kociolek J.P. 2016. Newly described Gomphonema and Gomphosphenia from Rocky Mountain Front Range streams, Colorado, USA, with additional discussion of rarely reported taxa. Diatom Research. 31(1-2): 51-62. | Morphology; Illustrations |
This page should be cited as:
Jüttner I. Gomphonema exilissimum (Grunow) Lange-Bertalot & Reichardt; 1996; 70. In: Jüttner I., Carter C., Cox E.J., Ector L., Jones V., Kelly M.G., Kennedy B., Mann D.G., Turner J. A., Van de Vijver B., Wetzel C.E., 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=3875. [Accessed:
].
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Record last modified: 27/12/2020