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Raphidiophrys capitata – arrows indicate plate scales

Raphidiophrys capitata Siemensma & Roijackers, 1988

Diagnosis: Scales elliptical, elongated, with rounded, often capitate poles; scale plates fuse peripherally with strongly inflexed sharp-edged rims; poles sometimes covered by a thin lamella; scales 6-14 x 2-4 µm, with a L/B-ratio of 3.0-5.4; scales with internal radiating septa; number of septa along de border varying from 30 to 60-70 per µm; edge of the scales strongly inflected.
Solitary forms were collected more often than colonial forms, which were observed only twice (Sweden). The colonies showed clusters of ca. 30 individuals. The cell diameter of colonial and solitary individuals varied between 25 and 50 µm. Axopods were long and abundant, up to 170 µm long.
The scales are long-elliptical, compared to those of R. intermedia. The scales are half the width of those belonging to R. intermedia and R. elegans. The general appearance of the scale is that of a boat; it has slight convex sides. Often the poles are clearly capitate, which gave the specific epithet. The poles are normally rounded. Widened, somewhat blunt poles are not rare. Both poles are often covered by a thin membrane, thus resembling a slipper. In cross section the scales show a crescent form. Numerous septa connect the upper with the lower plate of the scales. They radiate from the central axis.

Remarks: R. capitata was collected in Sweden, the Netherlands and Germany.

Raphidiophrys capitata
Raphidiophrys capitata: a cell; b plate scales, light microscopically; c common plate scale and two aberrant forms on its left side; d-e shoe shaped ends; f diameter of a plate scale; g edge of a plate scale (Ferry Siemensma, 1991)
Raphidiophrys capitata - Ferry Siemensma
Raphidiophrys capitata - Ferry Siemensma
Raphidiophrys capitata - Ferry Siemensma
Plate scale with shoe-shaped end
Raphidiophrys capitata - Ferry Siemensma
Raphidiophrys capitata; arrows indicate plate scales – river Weser, Germany
Raphidiophrys capitata
Raphidiophrys capitata
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