Key to the genus Crossodonthina

This key is partially based on Luo & Chen (2009) and Jiang & Wang (2021).

1 Eyes 2+2........................................................................................... 2

- Eyes 3+3........................................................................................... 5

2 Tubercle Oc with 2 chaetae......................................... C. hainana Xiong, Chen & Yin, 2005 (China)

- Tubercle Oc with 3 chaetae............................................................................. 3

3 Tubercles Di fused on Abd. V............................................ C. bidentata Luo & Chen, 2009 (China)

- Tubercles Di separated on Abd. V........................................................................ 4

4 Mandible with 3 rami and 1 basal tooth..................................... C. montana Lee & Kim, 1990 (China)

- Mandible with 2 rami and 2 basal teeth...................... C. langshanensis Hu, Jiang C. & Jiang J.G., 2019 (China)

5 Body macrochaetae smooth............................................................................. 6

- Body macrochaetae sheathed or serrated.................................................................. 9

6 Tubercle Di on Th. II–Abd. IV reduced, represented by some chaetae........................................... 7

- Tubercle Di on Th. II–Abd. IV well defined................................................................ 8

7 Tubercles De and Dl separated on Abd. V, mandible with 3 rami...................... C. nipponica Yosii, 1954 (Japan)

- Tubercles De and Dl fused on Abd. V, mandible with 4 rami.............. C. koreana Yosii & Lee, 1963 (Korea & Japan)

8 Cephalic tubercles Dl, L and So fused, mandible with 1 basal tooth.................... C. formosana Yosii, 1965 (China)

- Cephalic tubercles Dl, L and So independent, mandible with 3 basal teeth...... C. acuminata Jiang & Wang, 2021 (China)

9 Cephalic tubercles 2Di and 2De fused.................................... C. altamontana Yoshii, 1981 (Malaysia)

- Cephalic tubercles 2Di and 2De separated................................................................ 10

10 Tubercle Oc with 2 chaetae, tubercle Di, De, Dl on Th. I with 3, 2, 3 chaetae respectively............................................................................................... C. radiata (Salmon, 1941) (New Zealand)

- Tubercle Oc with 3 chaetae, tubercle Di, De, Dl on Th. I with 1, 2, 1 chaetae respectively........................... 11

11 Mandible with dendritic rami.......................................................................... 12

- Mandible without dendritic rami........................................................................ 14

12 Tubercles De and Dl fused on Abd. V, mandible with fringed lamella............. C. tridentiens Yue & Yin, 1999 (China)

- Tubercles De and Dl separated on Abd. V, mandible without fringed lamella..................................... 13

13 Maxillary head with ciliates, macrochaeta pointed, body monocolor......................................................................................... C. laterisensillata Ohira, Kataoka, Tanooka & Nakamori, 2022 (Japan)

- Maxillary head without ciliates, macrochaeta blunt, body bicolor.......................... C. elegans sp. nov. (Japan)

14 Cephalic tubercle L separate from So, mandible with 2 basal teeth.................. C. alatoserrata Yosii, 1965 (China)

- Cephalic tubercle L fused to So, mandible with at least 3 basal teeth............................................ 15

15 Mandible with 3 rami and 5 basal teeth........................... C. tiantongshana Xiong, Chen & Yin, 2005 (China)

- Mandible with 5 rami and 3 or 4 basal teeth............................................................... 16

16 Tubercle De on Th. II with 5 (4+s) chaetae, mandible with 3 basal teeth............ C. choui Jiang & Zhang, 2012 (China)

- Tubercle De on Th. II with 4 (3+s) chaetae, mandible with 4 basal teeth........... C. clavata Jiang & Wang, 2021 (China)