Sabulodinium
Sabulodinium Saunders & Dodge, 1984 (ref. ID; 7726 original paper)
[ref. ID; 7726]
Diagnosis; Cellula thoracata, a latere compressa; epitheca brevissima, aut complanata aut tholiformis; hypotheca compluribus bracteis obtecta. forma aut ovata aut irregularis; bracteae thecales leves. (ref. ID; 7726)
Description; Cell armoured, laterally compressed: epitheca small, flattened or domed: hypotheca oval and covered with several plates; chloroplasts absent. Found in damp sand. (ref. ID; 7726)
Etymology; The name is derived from L. Sabulum meaning sand. (ref. ID; 7726)
Type species; Sabulodinium undulatum (ref. ID; 7726)
- Sabulodinium inclinatum (Balech) Saunders & Dodge, 1984 (ref. ID; 7726 redescribed paper)
Basionym; Thecadinium inclinatum Balech, 1956 (p.40, Figs.34-37) (ref. ID; 7726)
- Sabulodinium undulatum Saunders & Dodge, 1984 (ref. ID; 7726 original paper)
Syn; Phalacroma kofoidi (colourless form) Herdman, 1924 (p.79, Fig.23) (ref. ID; 7726); Thecadinium kofoidii Larsen, 1984 (ref. ID; 7726)
Sabulodinium inclinatum (Balech) Saunders & Dodge, 1984 (ref. ID; 7726 redescribed paper)
Basionym
Thecadinium inclinatum Balech, 1956 (p.40, Figs.34-37) (ref. ID; 7726)
Descriptions
Cell armoured, slightly bilaterally flattened; irregularly ovoid in shape, epitheca about one third of cell length separated from hypotheca by girdle which ascends from ventral to dorsal side of cell. The epitheca consists of a number of plates (ca. 10) with an apical pore having a U-shaped slit surrounded by trichocyst pores. On the hypotheca there appear to be five plates, with scattered pores, plus a large sulcal region. Plate formula: undetermined. Size: length 52 um, width 50 um. Found at Holy Island, Northumberland and reported from Brittany. (ref. ID; 7726)
Notes
This clearly appears to be the organism described in outline only by Balech (1956). As yet we have only seen one cell and thus it has to been possible to describe all the plates. It cannot remain in the redefined genus Thecadinium since it has too many hapothecal plates so we propose its removal into our new genus Sabulodinum. It is possible that this organism is sometimes confused with Amphidinium semilunatum (e.g. Dodge 1982), but we now believe that species to be a genuine Amphidinium with no thecal plates. (ref. ID; 7726)
Sabulodinium undulatum Saunders & Dodge, 1984 (ref. ID; 7726 original paper)
Synonym
Phalacroma kofoidi (colourless form) Herdman, 1924 (p.79, Fig.23) (ref. ID; 7726); Thecadinium kofoidii Larsen, 1984 (ref. ID; 7726)
Diagnosis
Naturae habens propria sui generis; cuius cingula subdeclivis; hypotheca marginem in dorso praebet undulantem. Absunt chloroplasti. Bractae thecales cum formula: ?, 5''' 1''''. (ref. ID; 7726)
Descriptions
Epitheca only about one tenth of cell length, extended to form the anterior list to the girdle (the plates have not yet been determined). Girdle slightly descending from the ventral to dorsal side. Hypotheca +/- oval but with a distinctly undulating dorsal side although this is more marked in SEM preparations than in live cells. Thecal plates smooth but with scattered simple pores. There are five postcingular plates, all with distinctive shapes and there is one antapical plate situated in the right side of the cell. The sulcus forms a groove extending from the girdle to the antapex. Nucleus situated in the lower part of the cell: chloroplast absent but pigmented bodies may by present. Plate formula: c, s, 5''', 1''''. Size: length 35 um, width 25 um. Found at Holy Island, Northumberland and reported from Port Erin (Herdman) and the Danish Wadden Sea (Larsen). (ref. ID; 7726)
Notes
Under the light microscope it is extemely difficult to distiguish this species from Planodinium striatum or Herdman's original Amphidinium kofoidii var. petasatum (Herdman 1921). However, the SEM shows it to have a distinctly different plate pattern on the hypotheca and we therefore find it is necessary to create a new genus. It is probably the colourless form of Herdman (1924), supposed to be a variety of P. kofoidii, which she clearly indicates as having an undulating dorsal margin. (ref. ID; 7726)