Glenodinium pulvisculus, copyright Don Loarie.

Belongs within: Peridiniales.

Glenodinium and the horseshoe of light
Published 30 January 2012

Yes, it’s another dinoflagellate. The subject of the above photo (from here) is Glenodinium pulvisculus. Glenodinium is a genus of photosynthetic, mostly freshwater dinoflagellates in the family Glenodiniaceae, diagnosed by Fensome et al. (1983) by the possession of four apical plates and six postcingular plates. Fensome et al. included two genera in this family, Glenodinium and Glenodiniopsis. Glenodinium has a horseshoe-shaped eyespot, but Glenodiniopsis does not. The eye-spot presumably functions in phototaxis, though it is worth noting that Glenodiniopsis is positively phototactic even without one (Highfill & Pfiester 1992).

Glenodiniopsis uliginosa, from here.

The identity of Glenodinium has been somewhat confused over the years, due in part to confusion over the identity of its type species, G. cinctum (Loeblich 1980). As a result, many of the references to Glenodinium in the literature refer to unrelated species, while true Glenodinium appears relatively little-studied. One species of Glenodiniopsis, G. steinii, has fared a little better, and its ultrastructure was described in detail by Highfill & Pfiester (1992). Among the more interesting details they noted was that instead of the multiple chloroplasts this species had originally been described as having, it really possesses a single chloroplast but one with multiple lobes, so that if it is viewed in cross-section the lobes might appear as individual plastids.

Systematics of Glenodiniaceae
Glenodiniaceae (see below for synonymy)FT93
|--Sphaerodinium Woloszynska 1916FT93
| `--S. polonicumCW03 [=Glenodinium polonicum Woloszynska 1916S73]
|--Glenodiniopsis Woloszynska 1916FT93
| |--G. steiniiLCK03
| `--G. uliginosaC-SC04
`--Glenodinium Ehrenberg 1836FT93
|--*G. cinctum Ehrenberg 1836 [=Sphaerodinium cinctum]FT93
|--G. aciculiferumTP87
|--G. armatumTP87
|--G. bacciliferum Biecheler 1952S73
|--G. biebliiGE87
|--G. cristatum Balech 1961S73
|--G. danicumSW70
|--G. divergens (Ehrenberg) Dangeard 1938 [=Peridinium divergens]S73
|--G. edaxGE87
|--G. eurystomumGE87
|--G. gymnodiniumTP87
|--G. hallii Freudenthal & Lee 1963S73
|--G. lenticulaS73
| |--G. l. f. lenticulaS73
| `--G. l. f. globulare (Kisselew) Kisselew 1950 [=Diplopsalis lenticula f. globularis Kisselew 1935]S73
|--G. leptodermumGE87
|--G. lubiniensiformePA87
|--G. oculatumSW70
|--G. pulvisculusGE87
|--G. quadridensTP87
|--G. rubrumH15
|--G. steiniiTP87
`--G. uliginosumTP87

Glenodiniaceae [Glenodinidae, Glenodinieae, Glenodiniidae, Glenodiniineae, Glenodinioideae, Glenodiniopsidaceae, Glenodiniopsidae, Glenodiniopsinae]

*Type species of generic name indicated


[CW03] Carty, S., & D. E. Wujek. 2003. A new species of Peridinium and new records of dinoflagellates and silica-scaled chrysophytes from Belize. Caribbean Journal of Science 39: 136–139.

[C-SC04] Cavalier-Smith, T., & E. E. Chao. 2004. Protalveolate phylogeny and systematics and the origins of Sporozoa and dinoflagellates (phylum Myzozoa nom. nov.) European Journal of Protistology 40: 185–212.

[FT93] Fensome, R. A., F. J. R. Taylor, G. Norris, W. A. S. Sarjeant, D. I. Wharton & G. L. Williams. 1993. A classification of living and fossil dinoflagellates. Micropaleontology Special Publication 7: i–viii, 1–351.

[GE87] Gaines, G., & M. Elbrächter. 1987. Heterotrophic nutrition. In: Taylor, F. J. R. (ed.) The Biology of Dinoflagellates pp. 224–268. Blackwell Scientific.

[H15] Hedley, C. 1915. Presidential address. Journal and Proceedings of the Royal Society of New South Wales 49 (1): 1–77, pls 1–7.

Highfill, J. F., & L. A. Pfiester. 1992. The ultrastructure of Glenodiniopsis steinii (Dinophyceae). American Journal of Botany 79 (10): 1162–1170.

[LCK03] Leander, B. S., R. E. Clopton & P. J. Keeling. 2003. Phylogeny of gregarines (Apicomplexa) as inferred from small-subunit rDNA and β-tubulin. International Journal of Systematic and Evolutionary Microbiology 53: 345–354.

Loeblich, A. R., III. 1980. Dinoflagellate nomenclature. Taxon 29 (2–3): 321–324.

[PA87] Pfiester, L. A., & D. M. Anderson. 1987. Dinoflagellate reproduction. In: Taylor, F. J. R. (ed.) The Biology of Dinoflagellates pp. 611–648. Blackwell Scientific.

[S73] Sournia, A. 1973. Catalogue des espèces et taxons infraspécifiques de Dinoflagellés marins actuels publiés depuis la révision de J. Schiller. I. Dinoflagellés libres. Beihefte zur Nova Hedwigia 48: 1–92.

[SW70] Steidinger, K. A., & J. Williams. 1970. Dinoflagellates. Memoirs of the Hourglass Cruises 2: 1–251.

[TP87] Taylor, F. J. R., & U. Pollingher. 1987. Ecology of dinoflagellates. In: Taylor, F. J. R. (ed.) The Biology of Dinoflagellates pp. 398–529. Blackwell Scientific.

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