Key to Polyrhachis, subgenus Campomyrma, from Thailand and Laos

Key to Thai and Lao species of Polyrhachis, subgenus Campomyrma, based on workers (modified from Jaitrong et al., 2023).

1

• Petiole without distinct dorsolateral spines (Fig. 1D) => Polyrhachis sukarmani

• 

  Jaitrong et al. (2023), Fig. 9. Polyrhachis sukarmani (non-type worker, THNHM-I-00027252). A. Body in profile view; B. head in full-face view; C. body in dorsal view.

• Petiole with distinct dorsolateral spines (Fig. 1A–C) => 2

• 

  Jaitrong et al. (2023), Fig. 1. Dorsa of mesosoma and petiole. A. Polyrhachis quadrispinosa (paratype worker, THNHM-I-00027177); B. Polyrhachis lao (holotype, THNHM-I-00027051); C. Polyrhachis halidayi (non-type worker, THNHM-I-00027200); D. Polyrhachis sukarmani (non-type worker, THNHM-I-00027252).

2

• Dorsum of petiole with four long spines (Fig. 1A); vertex and gastral tergites II–IV without erect hairs; propodeal spine relatively long, longer than wide at base; antennal scape shorter than or about as long as head width => Polyrhachis quadrispinosa

• 

  Jaitrong et al. (2023), Fig. 7. Polyrhachis quadrispinosa (holotype worker, THNHM-I-00027172). A. Body in profile view; B. head in full-face view; C. body in dorsal view.

• Dorsum of petiole with two acute spines projecting posterolaterally and two denticles in between (Fig. 1B–C); vertex with two erect hairs but pilosity on gastral tergites variable; propodeal spine relatively short, shorter than wide or almost as long as wide at base; antennal scape longer than head width => 3

• 

  Jaitrong et al. (2023), Fig. 1. Dorsa of mesosoma and petiole. A. Polyrhachis quadrispinosa (paratype worker, THNHM-I-00027177); B. Polyrhachis lao (holotype, THNHM-I-00027051); C. Polyrhachis halidayi (non-type worker, THNHM-I-00027200); D. Polyrhachis sukarmani (non-type worker, THNHM-I-00027252).

3

• Mesonotum longer than broad; propodeal spine posteriorly directed with apex slightly up curved; pair of median denticles on dorsum of petiole rudimentary with round apices; first gastral tergite without erect hairs; in dorsal view, propodeal dorsum deeply concave => Polyrhachis lao

• 

  Jaitrong et al. (2023), Fig. 6. Polyrhachis lao (holotype, THNHM-I-00027051). A. Body in profile view; B. head in full-face view; C. body in dorsal view.

• Mesonotum broader than long; propodeal spine upward-directed; pair of median denticles on dorsum of petiole distinct with acute apices; first gastral tergite with sparse erect hairs; in dorsal view, propodeal dorsum only shallowly concave => Polyrhachis halidayi

• 

  Jaitrong et al. (2023), Fig. 2. Polyrhachis halidayi (non-type worker, THNHM-I-00027200). A. Body in profile view; B. head in full-face view; C. body in dorsal view.

References

• Jaitrong, W., Yamane, S., Samung, Y., Noon-anant, N. 2023. The ant subgenus Campomyrma of the genus Polyrhachis Smith, 1857 (Hymenoptera, Formicidae, Formicinae) in Thailand and Laos, with descriptions of two new species. Zootaxa 5271(2), 294–312 (doi:10.11646/zootaxa.5271.2.5).