Polyrhachis halidayi

Polyrhachis halidayi inhabits both primary (dry evergreen, mixed deciduous, hill evergreen) and disturbed forests from lowland to highland (250–1500m a.s.l.). Although Wong and Guénard (2020) reported these ants nesting sites as arboreal in-between leaves, our data show that the species use rotting wood on forest floor, dead bamboo stems, and twigs on trees as nesting sites (Jaitrong et al., 2023).

Identification
Jaitrong et al. (2023) - Polyrhachis halidayi is similar to Polyrhachis quadrispinosa and Polyrhachis lao. They share the scalelike petiole, with two acute spines projecting dorsolaterally, and two denticles in between. However, P. halidayi can be easily separated from the latter two by the propodeal spine, short and pointed upward (propodeal spine longer, subtriangular, pointed backward in the latter two); first gastral tergite with sparse standing hairs (without hairs in the latter two).

Polyrhachis halidayi belongs to Polyrhachis creusa species group. It is similar to Polyrhachis creusa. However, P. halidayi can be separated from P. creusa by:
 * 1) erect hairs on gastral tergites I and II (without hairs in P. creusa)
 * 2) weak or without striation on pronotum (distinct striation on pronotum in P. creusa)
 * 3) anterior clypeal margin convex medially without denticles (feebly concave and serrate in P. creusa)

Distribution based on Regional Taxon Lists
Oriental Region: India, Laos, Myanmar, Thailand, Vietnam. Palaearctic Region: China.

Nomenclature

 *  halidayi. Polyrhachis halidayi Emery, 1889b: 517 (w.) MYANMAR. Bingham, 1903: 413 (q.). Combination in P. (Campomyrma): Emery, 1925b: 180.

Type Material

 * Syntype worker from Myanmar, Tenasserim, Kawkareet (.

References based on Global Ant Biodiversity Informatics

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