Bryceella perpusilla Wilts, Martinez Arbizu and

Lee, Sue Yeon, Yoo, Jung Sun & Kim, Seung Tae, 2017, New records of 13 rotifers including Bryceella perpusilla Wilts et al., 2010 and Philodina lepta Wulfert, 1951 from Korea, Journal of Species Research 6, pp. 26-37 : 27

2. Bryceella perpusilla Wilts, Martinez Arbizu and

Ahlrichs, 2010 ( Fig. 1)

Bryceella perpusilla Wilts, Martinez Arbizu and Ahlrichs, 2010, pp. 474-478 , figs. 1-4.

Material examined. Two specimens found in mosses and tree bark around Sangwonsa, Odaesan, Jinbu-myeon, Pyeongchang-gun, Gangwon-do, 37°47 ʹ 18.5 ʺ N 128°33 ʹ 50.6 ʺ E, 25 Sept. 2016.

Diagnosis. Corona ventral and with two short apical styli. Rostrum triangular. Foot about 1/5 of total length and with two pseudosegments. Toes shorter than second foot pseudosegment; thin and curved outwardly. Vitellarium with four nuclei. Inner margins of right ramus with three and left ramus with two cone-shaped projections anteriorly; right uncus 6-toothed and left uncus 5-toothed; manubria long and slender.

Measurements. Total body length 127 μm. Greatest trunk width 33 μm. Foot length 21 μm.

Remarks. According to Wilts et al. (2010), B. perpusilla might be one of the smallest rotifers because the body lengths of the type specimens were just 50-80 μm. The Korean specimens were larger than the type specimens as described above.

This species is distinguished from other congeners by the very small size, the slender body outline, the short apical styli, the triangular rostrum, the outward curving, blunt and rod-shaped toes, the four-nucleated vitellarium (york gland), the slender manubria and the caudally directed alulae ( Wilts et al., 2010). In the Korean specimens, rostrum was rather round than triangular in the frontal view.

B. perpusilla was found in terrestrial mosses in Northwest Germany in 2008. Eight years later, it was rediscovered in mosses and tree barks around Sangwonsa, Odaesan in Korea, which was the second record of this species.

World distribution. Germany and Korea.

Deposition. Deposited in the collection of the National Institute of Biological Resources, Incheon, Korea (ZII YIV0000004842, ZIIYGR0000000008).