Unixenus, Jones, 1944

Huynh, Cuong & Likhitrakarn, Natdanai, 2023, First records of penicillate millipedes (Diplopoda, Polyxenidae) from Thailand, with descriptions of two new species, Zootaxa 5383 (4), pp. 514-536 : 533-534

Key to described species of Unixenus

This key was adapted from Short and Huynh (2020). The type species from India, U. padmanabhai , is not included due to insufficient detail in the published record .

1. Lateral palp of gnathochilarium with 13 conical sensilla...................................................... 2

- Lateral palp of gnathochilarium with 22 (female), 24 (male) conical sensilla............... Unixenus thailandicus sp. nov.

2. Setae without projecting spines on legs.................................................................... 3

- Setae with projecting spines on legs....................................................................... 7

3. Femur with only one seta, tibia of legs 6–13 without setae..................................................... 4

- Femur with at least two setae, tibia with one seta........................................................... 6

4. Antennomere V with 3 bacilliform sensilla................................................................. 5

- Antennomere VI with 4 bacilliform sensilla on................................................... U. myallensis

5. Telotarsus with more than 4 processes on claw....................................................... U. attemsi

- Telotarsus with 4 or less processes on claw....................................................... U. broelemanni

6. No seta on tarsus 1 of legs 3–13, setiform sensillum between bacilliform sensilla 1 and 2 on antennomere VI..................................................................................................... U. corringlensis

- Seta present on tarsus 1 of legs 3–13, no setiform sensillum between bacilliform sensilla 1 and 2 on antennomere VI............................................................................................. U. carnarvonensis

7. One seta only on femur, no setae on tibia....................................................................8

- At least 2 setae on femur, 1 seta on tibia................................................................... 9

8. Four bacilliform sensilla on antennomere VI, 5 ornamental trichomes c ................................. U. corticolus

- Three bacilliform sensilla on antennomere VI, 3 ornamental trichomes c................................ U. vuillaumei

9. Three bacilliform sensilla on antennomere VI.............................................................. 10

- Four bacilliform sensilla on antennomere VI................................................... .. U. barrabaensis

10. A setiform sensillum present between bacilliform sensilla 1 and 2............................................. 11

- A setiform sensillum present in anterior of bacilliform sensilla 1................................................ 13

11. Telotarsus with robust claw................................................................... U. mjoebergi

- Telotarsus with slender claw............................................................................ 12

12. Posterior process longer than ½ length of the claw............................................. U. intragramineus

- Posterior process shorter than ½ of the claw...................................................... U. moniqueae

13. Three ornamental trichomes c per side, two pairs of coxal glands in male.............................. U. mossmanus

- 5–9 ornamental trichomes c, six pairs of coxal glands in male....................................... U. karajinensis