Habrotrocha serpens Donner, 1949

Zeng, Yue, Wei, Nan, Wang, Qing, Iakovenko, Nataliia S., Li, Ying & Yang, Yufeng, 2020, Bdelloid rotifers (Rotifera, Bdelloidea) of China: diversity and new records, ZooKeys 941, pp. 1-23 : 1

Habrotrocha serpens Donner, 1949 Figure 5 ; Table 3

Materials.

Five specimens found in dry mosses on bark from southern China (GD6) (Table 2 ).

Description.

Body extremely slender (BW is only about 6% of TL), long and cylindrical, integument transparent and smooth. Rostrum rather long, with two pseudosegments. The first pseudosegment circular and slightly bigger than the second one which often contracted (Fig. 5B ). One whole semi-circular lamella not divided into lobes, rather large, broader than the rostrum, covers the long and stiff tactile cilia. Head slender, HW 44% of HL, 22% of TL. Corona also slender, a little wider than the head, CW 107% of HW. Trochal pedicels grown together, central rounded papillae on each separated trochal discs, incline to the dorsal side. Upper lip low, narrow and without lobes, slightly arched, not covered by the incompletely extended rostrum. Lower lip spoon-shaped, strongly protrudes forward.

Neck slender. Throat very short, pharyngeal tube long, undulating before the mastax. Dorsal antenna slender, with two segments, its length 86% of the antennal pseudosegment width. Trunk slender, the two lateral sides of trunk almost parallel when animal fully extended, the last trunk segment often strongly contracted. Rump conical, with both pseudosegments swollen, arched up dorsally and roofing the foot, RL 12% of TL.

Foot very short, of four pseudosegments, FL 5% of TL. Spurs triangular and have swollen base, each with curved inner margins and a very small interspace. SL 63% of SSW. Three short unsegmented and of approximately equal length toes (Fig. 5C ). Trophi large, dental formula 4/4.

Measurements.

The detailed measurements are summarized in Table 5 with a comparison of the original data from Donner (1949; 1970).

Remarks.

The general morphology of our sample conforms with the description of the Austrian population except that the rostrum is not always fully expanded to/exceeding the upper lip in a feeding position. It may because of the second pseudosegment of rostrum often contracted. Additionally, we observed three approximately equal-lengthed toes which were not clear in Donner’s (1949) description.

This morphospecies was first described from soil from Austria by Donner (1949), and then recorded in moss and soil from Austria and Czechoslovakia ( Bartoš 1951); in needle litter, Calamagrosits turf, grasses and leaf litter from Austria, Czechoslovakia, Romania, and Spain ( Donner 1965, 1970). It is new for China as well as for the Oriental region.

Figures

Figure 5. Habrotrocha serpens Donner, 1949 A, B habitus, creeping (not fully extended), dorsal view C three toes, dorsal view D, E head, ventral view F, G head, lateral view (the second pseudosegment of rostrum contracted). Scale bars: 50 μm (A, B); 10 μm (C-G).