Peridiniopsis
- Peridiniopsis berolinense (Lemmermann, 1900) (ref. ID; 4126)
Syn; Peridinium berolinense Lemmermann, 1900 (ref. ID; 4126)
- Peridiniopsis borgei Lemmermann (ref. ID; 7121)
Synonym
Peridinium berolinense Lemmermann, 1900 (ref. ID; 4126)
Comments
When first described in 1900 by Lemmermann (as Peridinium berolinense), Peridiniopsis berolinense was described as possessing numerous small, green chloroplasts. A parenthesized question mark after this description indicated that he was unsure of this character. Expanding his description in 1910, he wrote that since he hadn't observed living cells, he couldn't determine whether the fine green granules were actually chloroplasts. He concluded that this species might be apochlorotic. Because of this uncertainly, some subsequent authors (e.g. Eddy 1930; Huber-Pestalozzi 1950; Schiller 1933; Schilling 1913) simply stated that in this species the chromatophores, if present, were hard to discern. Thompson, on the other hand, believed that this species was "without chromatophores though spherical colorless or pigmented masses may be present" (Thompson 1950). Our observations with the TEM verify Thompson's belief and demonstrate that Peridiniopsis berolinense is an apochlorotic species. Ultrastructurally P. berolinense possesses a number of features common to the Dinophyceae. These include a nucleus with permanently condensed chromosomes, a pusule which corresponds to Dodge's (1972) "simple tubular pusule", a cell covering containing thecal vesicles and plates, mitochondria with tubular cristae, and, normally two dissimilar flagella lying in their respective furrows. With respect to the cell covering, the theca of P. berolinense falls into the sixth category of Dodge & Crawford's (1970) nine-group description of dinoflagellate thecal types: "medium thickness plates with distinct flanges; plates reduced in number and showing diversity of form". The possession of trichocysts and their associated pores is quite typical of dinoflagellates, and the linear arrangement of these pores in the plates along the cingulum has also been observed in Ostreopsis ovata Fukuyo (Besada et al. 1982) and Gymnodinium acidotum Nygaard (Wilcox et al. 1984). Longitudinally biflagellate dinophyceans have been reported by several workers, as mentioned by von Stosch (1973), who also noted that in Gymnodinium pseudopalustre Schiller and Woloszynskia apiculata von Stosch, some of the sexual stages "retain the two posterior flagella of their component gametes, whereas one of the transverse flagella seems to get lost at some stage". Recently, Soyer et al., (1982) reported LB Prorocentrum micans Ehrenberg cells and offered several hypotheses to account for their increased occurrence in older cultures, including the theory that such cells represented sexual stages. As this increase in numbers of LB cells is precisely the situation found in our older cultures of P. berolinense, these cells may also represent sexual stages. Alternatively, the motor organelles may duplicate just prior to cell division; however, since the density of dinoflagellate cells in our cultures rather low and the cells themselves are not dividing very rapidly, that hypothesis seems unlikely. (ref. ID; 4126)
Descriptions
Free-living. GenBank accession number EF058241. (ref. ID; 7121)
Geographic origin
St. Kalkbrottsdammen, Skane, Sweden. (ref. ID; 7121)