Crossodonthina, Yosii, 1954

Jiang, Jigang & Wang, Qingyun, 2025, A new species of Crossodonthina Yosii (Collembola, Neanuridae) from Central-South China, with the redescription of C. hainana Xiong, Chen & Yin, 2005, Zootaxa 5665 (2), pp. 187-204 : 203

Identification key to the world species of Crossodonthina *

1 Eyes 2+2, the montana species group..................................................................... 2

- Eyes 3+3, the nipponica species group.................................................................... 6

2 Tubercle Oc with 2 chaetae, Fu with 6 chaetae........................... C. hainana Xiong, Chen & Yin, 2005 ( China)

- Tubercle Oc with 3 chaetae, Fu usually with less than 6 chaetae................................................ 3

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

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

4 Mandible with 1–2 basal teeth and less than 5 rami........................................................... 5

- Mandible with 4 basal teeth and 5 rami............................... C. quadridentata Jiang & Wang, 2024 ( China)

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

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

6 Body macrochaetae smooth, pointed and not sheathed........................................................ 7

- Body macrochaetae sheathed and blunt, or serrated......................................................... 11

7 Tubercle Di on Th. II–Abd. IV reduced, represented by some chaetae........................................... 8

- Tubercle Di on Th. II–Abd. IV well defined................................................................ 9

8 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)

9 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 more than 1 basal tooth.............................. 10

10 Antenna IV with 6 chaetae s (S3–S8), Cephalic tubercle Di with 2 chaetae, tubercle Dl of Th. I with 2 chaetae..................................................................................... C. jiuyishanensis sp. nov. ( China)

- Antenna IV with 8 chaetae s (S1–S8), Cephalic tubercle Di with 1 chaeta, tubercle Dl of Th. I with 1 chaeta............................................................................... C. acuminata Jiang & Wang, 2021 ( China)

11 Tubercle Di on Abd. I–IV reduced, represented by some chaetae, cephalic tubercles Di and De fused....................................................................................... C. altamontana Yoshii, 1981 ( Malaysia)

- Tubercle Di on Abd. I–IV developed, cephalic tubercle Di free from De......................................... 12

12 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 of Th. I with 1, 2, 1 chaeta respectively............................ 13

13 Mandible without dendritic rami........................................................................ 14

- Mandible with dendritic rami.......................................................................... 17

14 Cephalic tubercle L separated 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 5 basal teeth and 3 rami............................ C. tiantongshana Xiong, Chen & Yin, 2005 ( China)

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

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

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

17 Tubercles De and Dl fused on Abd. V, mandible with 4 main rami................ C. tridentiens Yue & Yin, 1999 ( China)

- Tubercles De and Dl separated on Abd. V, mandible with 5 main rami.......................................... 18

18 Body monocolor, body macrochaetae pointed, cephalic tubercle Dl with 2–4 microchaetae....................................................................... C. laterisensillata Ohira, Kataoka, Tanooka & Nakamori, 2022 ( Japan)

- Body bicolor, macrochaeta knobbed, cephalic tubercle Dl with 3 chaetae (Ml+ 2 mi)........................................................................................... C. elegans Kasai, Tanaka & Sawahata, 2023 ( Japan)

* Key partially based on Jiang & Wang (2021) and Kasai et al. (2023)