Habrotrocha tripus ( Murray, 1907 )

Song, Min Ok & Lee, Chang-Ho, 2021, New records of three monogonont and seven bdelloid rotifers from Korea, Journal of Species Research 10 (4), pp. 392-404 : 397-398

5. Habrotrocha tripus ( Murray, 1907) ( Fig. 5 )

NjȐḍĒÊệ (ṵḋ)

Callidina tripus Murray, 1907, p. 99 , figs. 5-7.

Habrotrocha tripus : Donner, 1965, p. 51, fig. 35a.

Material examined. One specimen sorted out from leaf litter and soil at Gyeongpo Wetland, Unjeong-dong, Gangneung-si, Gangwon-do, 37°47′32.0″N, 128°54′14.2″E, 3 June 2021.

Diagnosis. Body slightly granulated. Corona narrower than cingulum. Sulcus very narrow and trochal discs almost attached each other. Upper lip much lower than trochal discs; arched and round medially; without any projections. Cingulum pad slightly wider than cingulum. Trunk plump and spindle-shaped in feeding. Rump gradually tapering to foot. Foot with four pseudosegments. Spurs conical and with narrow interspace; inner margins with slight hump proximally. Dorsal toe extended in feeding.

Measurements. Total length in feeding 247 μm. Corona width 26 μm. Cingulum width 31 μm. Cingulum pad width 32 μm. Greatest trunk width in feeding 76 μm. Spur length 8.5 μm.

Remarks. One of the diagnostic characteristics of Habrotrocha tripus ( Murray, 1907) is the dorsal toe which always remains extended. In the Korean specimen, the dorsal toe was not always extended, but it protruded often even during feeding ( Fig. 5B, C ). In bdelloids, toes usually stretch out during their creeping movement, not in feeding.

The upper lip of the Korean specimen had round and broad median lobe, while that of the type specimen had rather narrow median lobe. The general morphology of feeding head of the Korean specimen was most similar to that of the specimen reported by Donner (1965) except the small median projection on the upper lip ( Donner, 1965, Fig. 35a).

This species has been reported from Europe, South America, New Zealand ( Donner, 1965) and Turkey ( Kaya et al., 2009). The present study is the first Asian record of this species.

World distribution. Europe, Korea, New Zealand, South America and Turkey.

Deposition. Deposited in the collection of the Nakdonggang National Institute of Biological Resources, Sangju-si, Gyeongsangbuk-do, Korea (NNIBR2021523IV481).

Figures

Fig. 5. Habrotrocha tripus(Murray, 1907).A. feeding head, dorsal view; B. feeding habitus, ventral view(an arrow pointing at the dorsal toe); C. foot, spurs and toes, ventral view (an arrow pointing at the dorsal toe)(Scales:A, C=20μm; B=50 μm).