Macrotrachela nixa Donner 1962

Macrotrachela nixa Donner, 1962

Figure 5

Material. Korea: Two specimens found in mosses and lichens at Cheongnyangsan, Bonghwa-gun, Gyeongsangbuk-do.

This species has been reported only from New Zealand (Haigh 1971) and the Antarctic (Sudzuki 1979) after its description from Spain by Donner (1962)

The feeding head morphology of this species is similar to that of Macrotrachela musculosa Milne, 1886 in that it has a depression between two medial lobes on the upper lip. However, the depression between two lobes is wider than each lobe’s width and slightly convex in this species, while that of M. musculosa is narrower than each lobe’s width and with a small projection medially. In addition, the ratio of height to width of upper lip is bigger in M. musculosa. This species is also distinguished from M. musculosa by shorter head length in feeding, wider corona, cylindrical neck in feeding, and narrower trunk in feeding.

Measurements. Body length in feeding 293 µm. Corona width 74–78 µm. Collar width 49–53 µm. Greatest neck width in feeding 50–52 µm. Greatest trunk width in feeding 61–63 µm. Spur length 10 µm.