Macrotrachela decora ( Bryce, 1912 )

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 : 401-402

10. Macrotrachela decora ( Bryce, 1912) ( Fig. 10 )

ŀêǖĒÊệ (ṵḋ)

Callidina decora Bryce, 1912 , pp. 369, 370, fig. 3.

Macrotrachela decora : Donner, 1965, pp. 138, 139, fig. 102.

Material examined. Two specimens found from mosses and soil at Daegwallyeong, Hoenggye-ri, Pyeongchanggun, Gangwon-do, 37°40′58.0″N, 128°45′41.6″E, 6 June 2021.

Diagnosis. Rostrum short. Rostral lamella wider than head end and bilobed; each lobe round. Corona much wid- er than cingulum. Pedicel very short. Sulcus width about a half of pedicel width; two fingertip-shaped processes on sulcus base medially. Upper lip arched and lower than sulcus base. Pharyngeal tube slightly longer than trophi length. Rump gradually tapering to foot and with rim posteriorly. Foot very short and with 4 pseudesegments; much narrower than rump. Spurs conical, very short, and with narrow interspace. Three toes; toe separation not clear.

Measurements. Total length in creeping 239 μm. Corona width 52 μm. Cingulum pad width 41 μm. Greatest trunk width in creeping 59 μm. Spur length 4.6 μm.

Remarks. Bryce (1912) wasn’t sure about the toe struc- ture in his original description of this species. He specu- lated that the toes were absent or modified to a sucker-like disc, in which case this species would properly belong to the genus Mniobia Bryce, 1910 . However, he tentatively placed this species in the genus Macrotrachela pending further examination. In the Korean specimen, the toes were not clearly separated from each other, and looked like a triangular tube ( Fig. 10E ), which is different from the adhesive disc or two stumpy papillae that the Mniobia species usually have instead of three or four toes. There- fore, the placement of this species in the genus Macrotrachela seems to be more plausible.

One of the most important diagnostic characteristics of this species is the two fingertip-shaped processes on sulcus base, which are clearly observed on the sulcus base of the Korean specimens ( Fig. 10C, D ).

This species has been reported from Czech Republic, Sweden ( Donner, 1965), New Zealand ( Haigh, 1963) and Turkey ( Ustaoğlu, 2015) after the description from the United Kingdom ( Scotland) by Bryce (1912). It is new to Asia.

World distribution. Czech Republic, Korea, New Zealand, Sweden, United Kingdom and Turkey.

Deposition. Deposited in the collection of the National Institute of Biological Resources, Incheon, Korea ( VSJAIV 0000000402 ) .

Figures

Fig. 10. Macrotrachela decora(Bryce, 1912).A, B. creeping habitus in different focal planes, dorsal view; C, D, feeding head, dorsal view; E. foot, spurs and toes, ventral view (Scales:A, B=50 μm; C, D=20 μm; E=10μm).