A. multilobata
A. multilobata – from Golemansky, 1964

Arcella multilobata  Golemansky, 1964

Diagnosis: Shell more or less in the shape of a sphere cap with a rounded edge, in ventral view circular, rarely elliptical. Pseudostome lobed: 6—10 shallow, rounded lobes agree with more or less pointed teeth. In lateral view, the dorsal face represents a segment of a circle or a portion of a parabola without marginal undulation. The angle of connection with the oral face is rounded. Oral face invaginating regularly towards the pseudostome and provided with a very short oral tube. The intussusception is 1/3—1/2 the height of the test. Shell wall yellowish, rarely dark with very fine areoles, but always visible.

Dimensions: According to Golemansky (1964): Shell diameter 84—98 µm; height 28—31 µm; aperture 20—24 µm; H/D ratio 0.30—0.38; invagination 12—16 µm.

Habitat: Wet mosses with rocks.

Geographical distribution: Guinea.

Remarks: Arcella lobostoma Deflandre, 1928 differs from A. multilobata by its substantially hemispherical shape (H/D: 0.65—0.68) and its irregularly quadrilobed pseudostome. The dimensions of A. lobostoma are smaller than those of A. multilobata. According to Deflandre 1928 the diameter of this first species is 42—54 µm.

Ferry Siemensma, created February 22, 2019; last modified January 10, 2025
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