Habrotrocha visa Donner, 1954

Song, Min Ok & Min, Gi-Sik, 2015, A new species and ten new records of bdelloid rotifers from Korea, Zootaxa 3964 (2), pp. 211-227 : 223

Habrotrocha visa Donner, 1954

Figure 7 d–f

Material. Two specimens found in mosses and leaf litter on a mountain in Mongsanpo, Seosan-si, Chungcheongnam-do, April 14, 2013.

The distribution of this species has previously been limited to seven European countries, including its type locality, Austria, since the original description by Donner (1954). The present study is the first one to record the species outside Europe.

This species closely resembles H. solitaria Donner, 1949 and H. eremita (Bryce, 1894) . Donner (1962) placed these three species in a “ solitaria - visa - eremita ” group, and examined the variations in body size, trophi length, feeding head length, dental formula, corona width, collar width, sulcus width, upper lip morphology, presence or absence of a projection on the sulcus, and egg size ( Donner 1962). The most distinguishable characteristic may be the ratio of the corona width to the collar width, which is 0.75–0.93 for H. solitaria , 0.92–1.11 for H. visa , and about 1.38 for H. eremita ( Donner, 1962) . There is a little overlap between H. solitaria and H. visa in the range of the ratio. The second most useful diagnostic characteristic is the width of the sulcus, which is very narrow in H. solitaria and very wide in H. eremita ( Donner 1962) . In the Korean specimens, the ratio of the corona width to the collar width is 1.09, and the sulcus widths lie between those of H. solitaria and H. eremita . The morphology of the feeding heads of the Korean specimens is most similar to that of the Austrian population, which was previously attributed to H. eremita by Donner (1949), and subsequently recognized as belonging to H. visa by Donner (1954) ( Donner 1949; 1950; 1954; 1962).

The general morphology of the Korean specimens conforms to those of the European populations, except that the body color is reddish. The Korean specimens have a triangular projection in the middle of the sulcus, but they don’t have any median process on the upper lip.

Measurements. Corona width 31 µm. Collar width 28.5 µm. Total length (in creeping) 221 µm. Spur length 5.6 µm

Figures

FIGURE 7. Habrotrocha longula Bryce, 1915. (a) creeping, lateral view; (b) feeding head, dorsal view; (c) foot, spurs and toes, ventrolateral view. Habrotrocha visa Donner, 1954. (d) creeping, dorsal view; (e) feeding head, dorsal view; (f) foot, spur and toes, lateral view (scale bars: a, d = 50 µm; b, e, f = 20 µm; c = 10 µm).