Resticula nyssa Harring & Myers, 1924

Sørensen, Martin Vinther, 2006, On the rotifer fauna of Disko Island, Greenland, with notes on selected species from a stagnant freshwater lake, Zootaxa 1241, pp. 37-49 : 43-45

Resticula nyssa Harring & Myers, 1924

A few specimens were found in the samples. The species is a rare cosmopolite and has also been recorded from Europe ( Wulfert 1940; Koch­Althaus 1962, 1963; Koste 1965, 1968, 1976; Berzins 1978), Tasmania ( Koste & Shiel 1991), the United States ( Harring & Myers 1924; Berzins 1978), Arctic Canada ( Nogrady & Smol 1989; De Smet & Bafort 1990; De Smet & Beyens 1995) and Svalbard ( De Smet 1988, 1993). The species is new to Greenland.

The species is distinguished by its trophi morphology and absence of a true eyespot. The recorded specimens were generally typical. Trophi from one specimen were prepared for SEM. The rami are large and triangular. The apical rami parts are lamellate, forming an apical basket ( Fig. 4 ). A pair of pleural rods with fanned ends is attached to the dorsal side of the rami ( Fig. 4 A). The fulcrum is long with a dorsally curved terminal tip. Unci have two teeth, furthermore, left uncus has five accessory teeth forming a fan. Manubria are composed of a well­developed proximal head and a caudal rod. The proximal head contains three chambers. Anterior and posterior chambers have large apertures; the medial chamber has a smaller aperture in the distal part of the manubrium head ( Fig. 4 A).

Measurements: Trophi 50 µm; rami 28 µm; fulcrum 29 µm; manubria 30 µm; unci 13 µm.

Figures

FIGURE 4. Resticula nyssa. SEM­photos of trophi. A: dorsal view. B: frontal view. mm – aperture of medial manubrium chamber; pr – pleural rod; ra – ramus.