Cactodera, Krall & Krall, 1978

Feng, Yaxing, Wang, Dong, Xiao, Dongxue, Pereira, Tiago José, Xuan, Yuanhu, Wang, Yuanyuan, Liu, Xiaoyu, Chen, Lijie, Duan, Yuxi & Zhu, Xiaofeng, 2018, Cactodera chenopodiae (Nematoda: Heteroderidae), a new species of cyst nematode parasitizing common lambsquarter (Chenopodium album) in Liaoning, China, Zootaxa 4407 (3), pp. 361-375 : 373

Key to species of Cactodera

(modified from Subbotin et al., 2010, Cid Del Prado Vera & Subbotin 2014)

1 Cyst generally two times or more longer than wide, mean L/W ratio = 2.3................................. C. estonica

- Cyst usually less than twice as long as wide, mean L/W ratio = 1.1–1.8........................................... 2

2 Eggshell punctate...................................................................................... 3

- Eggshell smooth..................................................................................... 10

3 Mean stylet length of J2s ± 26 µm......................................................................... 4

- Mean stylet length of J2s <26 µm......................................................................... 5

4 J2s tail length = 48–64 µm, hyaline region = 23–28 µm, fenestral diam. = 23–41 µm......................... C. thornei

- J2s tail length = 37–48 µm, hyaline region = 17–24 µm, fenestral diam. = 14–25 µm........................ C. eremica

5 Mean J2s body length ± 411 µm, mean tail length ± 42 µm..................................................... 6

- Mean J2s body length <411 µm, mean tail length <42 µm..................................................... 8

6 Mean J2s tail length <43 µm, b ratio <3.5.......................................................... C. milleri

- Mean J2s tail length ± 43 µm, b ratio> 3.5.................................................................. 7

7 Female L/W ratio <1.4, mean hyaline region of J2s <22 µm............................................... C. cacti

- Female L/W ratio ± 1.4, mean hyaline region of J2s ± 22 µm................................... C. chenopodiae sp. n

8 Fenestral diam. <25 µm................................................................................ 9

- Fenestral diam. ± 25 µm....................................................................... C. galinsogae

9 Hyaline region of J2s = 4–8 µm..................................................................... C. rosae

- Hyaline region of J2s = 16–23 µm.................................................................. C. evansi

10 Mean J2s tail length <40 µm........................................................................... 11

- Mean J2s tail length ± 40 µm............................................................................ 13

11 Mean J2s body length <406 µm, mean hyaline region <16 µm........................................ C. amaranthi

- Mean J2s body length ± 406 µm, mean hyaline region ± 16 µm................................................. 12

12 Cyst with distinct vulval cone, J2s stylet length =21.0–23.0 µm....................................... C. torreyanae

- Cyst without distinct vulval cone, J2s stylet length =23.4–25.0 µm......................................... C. salina

13 J2s stylet knobs anterior surface concave, DGO = 4.5–5.6 µm................................................. 14

- J2s stylet knobs anterior surface convex, DGO = 2.5–3.0 µm........................................... C. acnidae

14 Vulval denticles present, J2s tail length = 43–50 µm..................................................... C. weissi

- Vulval denticles absent, J2s tail length = 46–60 µm................................................... C. radicale