Crossodonthina, Yosii, 1954

Ohira, Atsuko & Nakamori, Taizo, 2025, Two new luminous species of Neanuridae (Collembola) and the discovery of bioluminescence in the genus Crossodonthina Yosii, Zootaxa 5659 (3), pp. 377-399 : 387-388

Identification key to the species of Crossodonthina *

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

- Eyes 3+3............................................................................................ 6

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 1 basal tooth.............................................. C. montana Lee & Kim, 1990 (Taiwan)

- Mandible with 2 or more basal teeth...................................................................... 5

5 Mandible with 2 or more basal teeth. Eyes black................ C. langshanensis Hu, Jiang C. & Jiang J.G., 2019 ( China)

- Mandible with 5 basal teeth. Eyes unpigmented......................... C. quadridentata Jiang & Wang, 2024 ( China)

6 Cephalic O chaeta absent............................................................................... 7

- Cephalic O chaeta present.............................................................................. 8

7 Four cephalic tubercles, 2 Di and 2 De, fused into a single median structure........ C. altamontana Yoshii, 1981 ( Malaysia)

- Four cephalic tubercles, 2 Di and 2 De, not fused with each other.................... C. formosana Yosii, 1965 (Taiwan)

8 Tubercles Di, De, Dl on Th. I with 3, 2, 3 chaetae, respectively................ C. radiata ( Salmon, 1941) ( New Zealand)

- Tubercles Di, De, Dl on Th. I with 1, 2, 1 chaetae, respectively................................................. 9

9 Tubercles De and Dl fused on Abd. V.................................................................... 10

- Tubercles De and Dl separated on Abd. V................................................................. 12

10 An additional sensory chaeta present on tubercle L of Abd. IV............................. C. leodeus sp. nov. ( Japan)

- An additional sensory chaeta absent on tubercle L of Abd. IV................................................. 11

11 Di2 chaetae on Th. II–Abd. V as microchaeta. Body tubercles poorly developed: Di tubercles on Th. I–Abd. IV reduced................................................................... C. koreana Yosii & Lee, 1963 ( Korea & Japan)

- Di2 chaetae on Th. II–Abd. V as macro- or mesochaeta. Body tubercles spherical.... C. tridentiens Yue & Yin, 1999 ( China)

12 De2 chaetae on head as macrochaeta.......................................... C. alatoserrata Yosii, 1965 (Taiwan)

- De2 chaetae on head as microchaeta or absent............................................................. 13

13 An additional sensory chaeta present on tubercle L of Abd. IV................................................. 14

- An additional sensory chaeta absent on tubercle L of Abd. IV................................................. 15

14 An additional sensory chaeta present on tubercle L of Abd. I– III.............. C. acuminata Jiang & Wang, 2021 ( China)

- An additional sensory chaeta absent on tubercle L of Abd. I– III...................... C. nipponica Yosii, 1954 ( Japan)

15 An additional sensory chaeta present on tubercle L of Abd. I– III............................................... 16

- An additional sensory chaeta absent on tubercle L of Abd. I– III............................................... 18

16 Maxillary head with cilia. Macrochaeta pointed. Dorsal side of Th. I red in living specimen......................... 17

- Maxillary head without cilia. Macrochaeta blunt. Dorsal side of Th. I yellow or white in living specimen.......................................................................... C. elegans Kasai, Tanaka & Sawahata, 2023 ( Japan)

17 Mandible with 3 rami and 5 basal teeth. Unguis inner tooth often with 1–3 tiny basal denticules.................................................................................. C. tiantongshana Xiong, Chen & Yin, 2005 ( China)

- Mandible with 6 rami and 3 basal teeth. Unguis inner tooth without basal denticules............................................................................ C. laterisensillata Ohira, Kataoka, Tanooka & Nakamori, 2022 ( Japan)

18 Five chaetae (4+s) on tubercle De of Th. II. Eyes black......................... C. choui Jiang & Zhang, 2012 ( China)

- Four chaetae (3+s) on tubercle De of Th. II. Eyes unpigmented.................. C. clavata Jiang & Wang, 2021 ( China)

*This key is partially based on Luo & Chen (2009), Jiang & Wang (2021) and Kasai et al. (2023).