Manguin ex Kociolek & Reviers 1996 Category: Centric
BASIONYM: Cyclotella bodanica var. intermedia Manguin ex Kociolek & Reviers 1996
REPORTED AS: Cyclotella intermedia (Houk et al. 2010 (invalid))
GENUS CONSIDERED: Puncticulata
Contributor: William Daniels - June 2012
Length Range: 12-34 µm
Striae in 10 µm: 11-13
Valves are disc-shaped and concentrically undulate, with both concave and convex centers. The valve is divided into two distinct parts, with the central part roughly 1/3 of the total diameter. Striae are alveolate and multiseriate, with 3-4 rows of fine porelli which are not readily seen in LM. Porelli spacing within rows is 45-50 in 10 µm. The striae are of mostly the same length, but are variably interrupted by short stria that give the appearance of branching costae near the margin. Isolated rimoportulae with simple external openings are observed at the central ends of 2 or 3 shortened striae. These rimoportulae are sometimes evenly spaced around the diatom and sometimes not. Internally, the rimoportulae are long, thin, and oriented oblique or perpendicular to the striae. The central area contains areolae and fultoportulae of varying size that are arranged randomly, to somewhat radially. Under SEM, the areolae are internally covered by cribra while the fultoportulae are bordered by 3 satellite pores. There may be a thin hyaline area (annulus) isolating the central-most areolae. Marginal fultoportulae are evenly spaced and located at the marginal ends of the costae.
Note that the combination and elevation in rank to species published in Houk et al. (2010), Cyclotella intermedia (Manguin) Houk, was invalid because it did not refer to the validating description of the species (Kociolek and Reviers 1996).
Basionym: Cyclotella bodanica var. intermedia
Author: Manguin ex Kociolek & Reviers 1996
Length Range: 23 µm
Striae in 10 µm: 11
Diametre 23 µ. Zone marginale avec 11 stries en 10 µ, finement lignées, 2 a 3 points isolés (flamettes) en 10 µ; Zone intermédiaire parcourue par des rangés irrégulieres de ponctuations. Zone centrale courverte de ponctuations éparses.
Houk, V., Klee, R. and Tanaka, H. (2010). Atlas of freshwater centric diatoms with a brief key and descriptions, Part III. Stephanodiscaceae A. Cyclotella, Tertiarius, Discostella. Fottea 10 (Supplement): 1-498.
Kociolek, J.P. and de Reviers, B. (1996). The diatom types of Emile Manguin. II. Validating descriptions and designations of types for the New Caledonia species. Cryptogamie Algologie 17:193-215.
Manguin, E. (1961). Contribution à la flore diatomique de l’Alaska: Lac Karluk, espèces critiques ou nouvelles. Revue Algologique, Nouvelle Série 5(4): 266-288.
Manguin’s original description is based on plankton samples from Lake Karluk, an oligotrophic lake on Kodiak Island, Alaska. It has also been found in surface sediments of Toolik Lake in northern Alaska and possibly in oligotrophic alpine lakes in Germany and Austria.
Toolik Lake is an oligotrophic lake in a tundra landscape. Cyclotella bodanica var. intermedia was found in the surface sediments at 8 m depth.