Tetracyclus emarginatus (Ehrenberg) W. Smith; 1856; 38
Key references
Williams D.M. 1987. Observations on the genus Tetracyclus Ralfs (Bacillariophyta) I. Valve and girdle structure of the extant species. British Phycological Journal. 22(4): 383-399.
Morphology
Size
28-58 µm long, 16-24 µm wide (at central constriction).
Shape
Valves with wide central inflation which is indented and has round to cuneate projections.
Symmetry
Isopolar, bilaterally symmetrical.
Striae
Striae slightly radiate and gently curved; 20-25 in 10 µm (Williams 1987).
Axial area
Sternum central, narrow.
Other features
Transverse ribs 3-4 in 10 µm, most are primary, some secondary or tertiary.
SEM morphology
Apical pore field located on the mantle. 1-3 rimoportulae in variable positions. Areolae of the striae more widely and irregularly spaced towards the sternum. Cingulum consisting of valvocopula, many copulae and a narrow pleura.
28-58 µm long, 16-24 µm wide (at central constriction).
Shape
Valves with wide central inflation which is indented and has round to cuneate projections.
Symmetry
Isopolar, bilaterally symmetrical.
Striae
Striae slightly radiate and gently curved; 20-25 in 10 µm (Williams 1987).
Axial area
Sternum central, narrow.
Other features
Transverse ribs 3-4 in 10 µm, most are primary, some secondary or tertiary.
SEM morphology
Apical pore field located on the mantle. 1-3 rimoportulae in variable positions. Areolae of the striae more widely and irregularly spaced towards the sternum. Cingulum consisting of valvocopula, many copulae and a narrow pleura.
Literature
References are given in chronological order.
Reference |
Citation |
|---|---|
| Smith W. 1856. A Synopsis of the British Diatomaceae. John van Voorst, London. 107 pp; pls 32-62, pls A-E | Morphology |
| Williams D.M. 1987. Observations on the genus Tetracyclus Ralfs (Bacillariophyta) I. Valve and girdle structure of the extant species. British Phycological Journal. 22(4): 383-399. | Morphology; Illustrations; Taxonomy; |
This page should be cited as:
Van de Vijver B., Jüttner I., Williams D.M. Tetracyclus emarginatus (Ehrenberg) W. Smith; 1856; 38. 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=4235. [Accessed:
].
Image Gallery
Record last modified: 05/07/2022