Philodina, Ehrenberg, 1830

Song, Min Ok & Lee, Chang-Ho, 2020, Descriptions of two new species of Philodina (Rotifera, Bdelloidea), with notes on seven rare bdelloids from Korea, Zootaxa 4772 (2), pp. 253-276 : 268

Key to the Korean species of genus Philodina

1. Cerebral eye spots absent.............................................................................. 2

- Cerebral eye spots present............................................................................. 16

2. Dorsal toe pair always extended; toes thick, plump and with pointed tips............................... P. duplicalcar

- Dorsal toe pair not always extended; toes otherwise.......................................................... 3

3. Two pairs of spurs; trochal discs almost adjoined...................................................... P. scabra

- One pair of spurs; trochal discs with space between them..................................................... 4

4. Trunk with coarse and dense granules..................................................................... 5

- Trunk smooth........................................................................................ 6

5. First trunk pseudosegment with a shield-shaped sculptured area dorsally; without wart-shaped hemispherical processes on trunk.................................................................................. P. cylpeata n. sp.

- First trunk pseudosegment otherwise; wart-shaped hemispherical processes on trunk dorsally and laterally.................................................................................................... P. verrucosa n. sp.

6. First foot pseudosegment with two small projections.................................................... P. childi

- First food pseudosegment without any projections........................................................... 7

7. Dental formula 4/4 – 5/5........................................................................ P. grandis

- Dental formula 2/2 – 3/3............................................................................... 8

8. Trochal discs inclined toward sulcus; upper lip trilobed medially; spurs thin, long and pointed................... P. lepta

- Trochal discs and upper lip otherwise; spurs otherwise....................................................... 9

9. Spur pseudosegment around spur base inflated and bilobed........................................... P. tumidipes

- Spur pseudosegment around spur base otherwise........................................................... 10

10. Interspace between spurs narrower than spur base width..................................................... 11

- Interspace between spurs much wider than spur base width................................................... 12

11. Sulcus as wide as trochal disc width; median lobe of upper lip wide and low; median lobe with two or three projections; pseudosegments in rump with expansion posteriorly....................................................... P. rapida

- Sulcus much narrower than trochal disc width; median lobe of upper lip narrow and high; median lobe with two lobes; pseudosegments in rump without expansion posteriorly..................................................... P. plena

12. Interspace between spurs 2–3 times as wide as spur base width................................................ 13

- Interspace between spurs as wide as or much wider than 4 times of spur base width............................... 14

13. Foot about 1/4 of total body length in creeping........................................................ P. vorax

- Foot about 1/7–1/9 of total body length in creeping................................................ P. triangularis

14. Upper lip bilobed medially; disc retractor U-shaped and bilobed medially....................................... 15

- Upper lip arched; disc retractor slightly convex and trilobed medially.................................... P. koreana

15. Spur longer than spur base width; interspace between spurs much wider than 4 times of spur base width........ P. proterva

- Spur as long as spur base width; interspace between spurs as wide as 4 times of spur base width............ P. parvicalcar

16. Trunk highly granulated.............................................................................. 17

- Trunk smooth....................................................................................... 18

17. First foot pseudosegment with transverse ridge dorsally; spurs longer than width of interspace.......... P. rugosa coriacea

- First foot pseudosegment without any process; spurs short and incurved; interspace about 3.5–4 times as wide as spur base width............................................................................... Philodina corrugata

18. Dorsal toe pair always extended a little or fully; upper lip concave medially...................... P. acuticornis odiosa

- Dorsal toe pair otherwise.............................................................................. 19

19. Spurs thumb-shaped and with small knob or sharp points at ends....................................... P. flaviceps

- Spurs conical, thin and long........................................................................... 20

20. Corona much wider than cingulum; upper lip arched.................................................. P. roseola

- Corona slightly wider than cingulum; upper lip bilobed medially and with a wide depression between lobes.... P. tranquilla