Colurella, Bory De St. Vincent, 1823

Wei, Nan, Jersabek, Christian D., Xu, Runlin & Yang, Yufeng, 2019, New species and records of Colurella (Rotifera: Lepadellidae) from South China, with a key to Chinese Colurella, Zootaxa 4586 (3), pp. 475-490 : 488

Key to Colurella species recorded in China, modified from De Smet et al. (2015)

1. One toe............................................................................. C. unicauda Eriksen

- Two toes, spread or appressed giving impression of single toe.................................................. 2

2. Lorica broad lenticular in lateral view; head aperture margins oblique, strongly directed ventrally; two short spread toes........................................................................................... C. obtusa (Gosse)

- Lorica elongate, plump or ovate, not broad lenticular in lateral view; head aperture margins not or only weakly directed ventrally............................................................................................... 3

3. Toes short, toe length/lorica length usually ± 1/4, always separate............................................... 4

- Toes long, toe length/lorica length usually Ż 1/3, spread or appressed............................................. 6

4. Lorica moderately slender; head aperture smaller than greatest lorica height; posterior end of lorica gradually merging into downward curving short projections....................................................... C. uncinata (Müller)

- Lorica moderately slender or plump; head aperture as long as or slightly smaller than greatest lorica height; posterior end of lorica gradually merging into downward curving short or more or less long projections.............................. 5

5. Lorica plump, ending in short, mostly downward curving acute tips.................. C. uncinata bicuspidata (Ehrenberg)

- Lorica moderately slender, ending in robust, mostly ventrally directed acute tips........... C. uncinata deflexa (Ehrenberg)

6. Lorica ovate, length/height Ṩ 1.7; head aperture margins almost rounded, usually highest in median part................ 7

- Lorica moderately slender or elongate, length/height À 1.7; head aperture margins variable, usually not rounded.......... 9

7. Posterior end of lorica asymmetrical, right side smoothly rounded or with shallow notch, left side tapering to acute tip............................................................................................. C. ovalis sp. nov.

- Posterior end of lorica symmetrical....................................................................... 8

8. Foot aperture without dorsal notch; lorica posterior end triangular in lateral view, tongue-shaped in ventral/dorsal view; toes usually appressed............................................. C. sanoamuangae Chittapun, Pholpunthin & Segers

- Foot aperture with wide u-shaped dorsal notch; toes spread.................................... Colurella sp. ( Fig. 5 )

9. Posterior end of lorica tapering to acute angles or tips, occasionally weakly extended or merging into hook-shaped latero-dorsally pointing projections............................................................. C. adriatica Ehrenberg

- Posterior end of lorica angular with blunt tip, obtuse or rounded................................................ 10

10. Foot aperture with or without inconspicuous dorsal notch; posterior end of lorica angular with blunt tip................ 11

- Foot aperture with conspicuous dorsal notch or incision, more or less deeply extending dorsally; posterior end of lorica obtuse or rounded.......................................................................................... 12

11. Animal slightly smaller (lorica length 60–82 µm; toe length 30–38 µm); lorica usually higher (length/height average 1.59 (1.50–1.85)); ventral sulcus with conspicuous median keel......................................... C. psammophila

- Animal slightly larger (lorica length 92 µm; toes length 42 µm); lorica relatively lower (length/height 1.87); ventral sulcus without median keel.............................................................. C. cf. psammophila ( Fig. 6 )

12. Animal usually larger (lorica length 71–110 µm); head aperture smaller than greatest lorica height; dorsal margin evenly curved; toes usually appressed......................................................... C. colurus (Ehrenberg)

- Animal usually smaller (lorica length 50–86 µm); head aperture almost as long as greatest lorica height; dorsal lorica margin almost straight anteriorly, posterior part strongly curved; toes spread or appressed................................. 13

13. Lorica usually higher (length/height 1.56–1.88); head and foot apertures shallower; toes spread..... C. hindenburgi Steinecke

- Lorica usually lower (length/height 1.75–2.15); head and foot apertures deeper; toes spread or appressed...................................................................................................... C. geophila Donner

Figures

FIGURE 5. Colurella sp. A, C. Left lateral view. B. Ventral view. D. Dorsal view. Scale bar: A–D: 50 µm.

FIGURE 6. Colurella cf. psammophila. A, C. Left lateral view. B, E. Ventral view. D. Dorsal view. Scale bar: A–E: 50 µm.