Macrotrachela sonorensis Örstan, 1995

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 : 215-217

Macrotrachela sonorensis Örstan, 1995

Figure 3 c–d

Material. Eight specimens found in mosses and leaf litter on a mountain in Jeongan-myun, Gongju-si, Chungcheongnam-do.

This species is easily diagnosed by its spurs, which are bow-shaped, long, stiff and with a wide interspace. It is very rare and has recently been rediscovered in Arizona, USA by Birky (reported on-line at http:// www.eebweb.arizona.edu/faculty/birky/BirkyLab.html) after description from Sonora, Mexico by Örstan (1995). The two previous reports were from desert areas, whereas the Korean specimens were found in mosses and leaf litter on a mountain. Our present record suggests that M. sonorensis is not limited to the desert.

The general morphology of the Korean specimens conforms to that of the type specimens, except that the lower head part after the rostrum does not have a swollen appearance during creeping. The median lobes of upper lips were either smooth or with three small processes positioned asymmetrically in the original specimens. The shape of the entire upper lip, especially in dorsal view, was not mentioned in the original description. The upper lips of the Korean specimens are triangular with a truncated median lobe. The median lobe is slightly concave and has a very low median projection ( Fig. 3 d); this can make the upper lip appear to have three small processes. The original description did not mention the morphologies of the sulcus and disc retractor. In the Korean specimens, the disc retractor is convex and the sulcus has two small triangular processes medially ( Fig. 3 d).

Measurements. Total length (in creeping) 270 µm. Greatest trunk width (in creeping) 39 µm. Corona width 48 µm. Collar width 41 µm. Spur length 19 µm.

Figures

FIGURE 3. Philodina grandis Milne, 1916. (a) creeping, dorsal view; (b) feeding head, dorsal view. Macrotrachela sonorensis Örstan, 1995. (c) creeping, dorsal view; (d) feeding head, dorsal view (scale bars: a, c = 50 µm; b, d = 20 µm).