Adineta beysunae Oerstan, 2018 Figure 3; Table 3

Material.

Numerous specimens found in leaf litter from three provinces (GD13-14, 25-26, YN7, JS1) across tropical and subtropical zones. One specimen found in dew on leaves from Southwest of China (YN8) (Table 2).

Description.

Body angulate, large and transparent. Sometimes the organs in the trunk show brown coloration. No eyespots. Rostral lamella flat and widened, with two lateral triangular auricular protrusions holding long rostral setae under them (the number of stiff under each could not be counted under microscope). Setae length varies from 11 to 30 μm . Head trapezoid, rather large and long, HW 80-110% of HLb, HLb 17-22% of TL, HW 13-20% of TL. Numbers of U-gaps denticles on rakes: 9-9 (N = 3), 10-10 (N = 4).

Neck distinct from head, the first two pseudosegments of neck narrower than HW. Trunk oval. Posterior end of the first rump pseudosegment with a pair of lateral angular knobs.

Foot of five pseudosegments with two pairs of lateral knobs on its first two pseudosegments, FL 14-22% of TL. Spurs long and sturdy, with short interspace, SL 6-8% of TL, 172-284% of SSW. Three short unsegmented toes. Ventral toe longer than two dorsal toes. Dental formula 2/2.

Measurements.

TL 289 ± 40 μm, HLb 49 ± 5 μm, HW 45 ± 4 μm, FL 49 ± 8 μm, SL 20 ± 1 μm, SSW 10 ± 1 μm, RkW (N = 2, with 9-9 denticles; N = 4, with 10-10 denticles) 21 ± 1 μm, RaL (N = 14) 15.9 ± 2 μm, TrW 7.3 ± 1 μm .

Remarks.

This is the second report of this morphospecies since its original description by Örstan (2018) in rainwater and plant debris from the United States. In the present study, A. beysunae was found in leaf litter and dew on leaves. And interestingly, it was abundant in 60% of all leaf litter samples. Our study suggested A. beysunae might have a habitat preference for leaf litter and temporary waterbodies.

Family Habrotrochidae Harring, 1913

Genus Habrotrocha Ehrenberg, 1838