Protokeelia cholnokyi F. E. Round & P. W. Basson
Creators: name: Lobban, Christopher S.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Chromista
Ochrophyta
Bacillariophyceae
Rhopalodiales
Rhopalodiaceae
Protokeelia
Protokeelia cholnokyi

description: Protokeelia cholnokyi (Giffen) F.E. Round & P.W. Basson Figs 114–117
RHOPALODIALES D.G. Mann: Rhopalodiaceae (Karsten) Topachevs'kyj & Oksiyuk
Ref. illus.: Giffen 1963, figs 27–29 (as Auricula cholnokyi Giffen); Round & Basson 1995a, figs 1– 9.
Samples: GU44I-1, GU44J-2, GU44Z-15
Dimensions: Length 16–19 µm, depth (from ventral corners to apex of dorsal curve) 10–14 µm; striae ca. 18 in 10 µm, measured transversally across striae near the ventral margin.
Diagnostics: Dorsal (convex) margin nearly circular to weakly reniform; two distinct indentations on the dorsal side of the valve. A ridge (or fold) on the ventral side of the valve arises from points that are not clearly indented and curves closer to the dorsal than the ventral margin. Spines absent.
Comments: The genus Protokeelia was established by Reimer & Lee (1984) for an endosymbiotic diatom isolated from a foram, and subsequently three new free-living species were described by Round (1993) and Round & Basson (1994, 1995b), all from Bahrain and neighboring Saudi Arabia. The literature was reviewed by Round & Basson (1995a), who re-examined Auricula cholnokyi and transferred it and A. quinquelobata Voigt to Protokeelia, so there are now six species. Although Round & Basson (1995b) wrote that “each new site visited seems to yield a new species,” no further reports of new species have been published in the last 20 years; however, it seems unlikely that the biodiversity of Protokeelia has been exhausted, particularly elsewhere in warm waters. The known species have all been epipelic; the specimens we have seen were collected in algal turfs but these samples typically contain sediment.
The terminology is somewhat confusing, because the valve shows only one side as usually lying with the raphe on a ridge along the convex (dorsal) margin and the ventral margin more or less concave. The side thus showing is the ventral part of the valve, while the dorsal part is narrower and has the indentations (clearly seen in the whole frustule SEM, Fig. 117). The distinction between P. cholnokyi and P. quinquelobata has not been examined in SEM, but Round & Basson (1995a) assert that “the shape of the valve and of the ridge on the ventral face” suggest the two species are distinct. Voigt’s (1960, pl. 2, figs 8, 9, 10) taxon is more reniform and the ventral ridge arises and curves closer to the ventral margin than is the case in P. cholnokyi. Reexamination of Voigt’s material is needed to verify the distinction. The taxon given in Witkowski et al. (2000, p. 410, pl. 215, figs 11, 12) as “ Protokeelia cholnokyana (Giffen) Round et Basson ” is described as “narrowly reniform” and is much shallower than specimens illustrated by Giffen and Round & Basson.
description: Published as part of Lobban, Christopher S., 2015, Benthic marine diatom flora of Guam: new records, redescription of Psammodictyon pustulatum n. comb., n. stat., and three new species (Colliculoamphora gabgabensis, Lauderia excentrica, and Rhoiconeis pagoensis), pp. 1-49 in Micronesica 2015 (2) on page 12, DOI: 10.5281/zenodo.12117576