Polyrhachis lao

The Lao specimens (colony WJT10-LAO-42) of Polyrhachis lao were collected from a plantation. The nest was in a dead wood hanging on a shrub.

Identification
Polyrhachis lao is most similar to Polyrhachis halidayi, from which the former is easily separated by the characteristics mentioned in the key.

It is similar to the species of the Polyrhachis xiphias group in sharing the condition of median clypeal carina, but in the P. xiphias-group the dorsal ridge of the petiole between the lateral spines is entire, without median spines or denticles.

Khachonpisitsak et al. (2020) treated this species as Polyrhachis shixingensis of the P. xiphias-group, a larger species recorded from China and Vietnam, but the treatment was based on misidentification. Polyrhachis lao is also similar to Polyrhachis quadrispinosa; differences between the two species are given in the key.

Distribution
The report of Polyrhachis shixingensis from Thailand is a misidentification of this species (Jaitrong et al., 2023).

Distribution based on Regional Taxon Lists
Oriental Region: Laos, Thailand.

Nomenclature

 * . Polyrhachis lao Jaitrong & Yamane, in Jaitrong et al., 2023: 303, figs. 1B, 6 (w.) LAOS.

Type Material

 * Holotype worker (THNHM-I-00027051, THNHM), central Laos, Vientiane Province, Naxythong District, Sivilay Village, 18º15′′N, 102º27′E, 9.VI.2010, Sk. Yamane leg., LA10-SKY-021.
 * Paratypes: 5 workers (THNHMI-00027052 to THNHM-I-00027054, THNHM; SKY090610-1 to SKY090610-2, SKYC), same data as holotype; 8 workers (THNHM-I-00027055 to THNHM-I-00027062, THNHM), central Laos, Vientiane Province, Naxythong District, Sivilay Village, from dead wood, 9.VI.2010, W. Jaitrong leg., WJT10-LAO-42.