Polyrhachis cyaniventris

Habitats range from degraded primary dipterocarp forests to secondary forests and even extensively used coconut groves with rich undergrowth in lowlands and low montane regions. The second author frequently collected workers and gynes during daytime foraging on leaves and twigs of small trees and bushes, rarely on the ground, but did not encounter nest sites. Gary Alpert (in litt.) found nests occupying cavities in branches, both on the ground and in low vegetation; one nest had approximately 100 individuals and a single queen. (Sorger and Zettel 2009)

Identification
A member of the Polyrhachis cyaniventris species-group. Sorger and Zettel (2009) - Although P. cyaniventris is clearly more pilose than Polyrhachis pirata, pilosity appears strongly variable. It is suspected that this is caused by partially rubbed off setae.

Distribution
Philippines: Central and Southern Luzon, Catanduanes, Mindoro, Samar, Leyte.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Philippines.

Nomenclature

 *  cyaniventris. Polyrhachis cyaniventris Smith, F. 1858b: 70, pl. 4, fig. 47 (w.) PHILIPPINES. Forel, 1910d: 128 (q.). Combination in P. (Myrma): Emery, 1925b: 201. Senior synonym of cyaneus: Roger, 1863b: 9. See also: Sorger & Zettel, 2009: 30.
 * cyaneus. Polyrhachis cyaneus Mayr, 1862: 684, pl. 19, fig. 6 (w.) PHILIPPINES. Junior synonym of cyaniventris: Roger, 1863b: 9.

Worker
Sorger and Zettel (2009) - Holotype of Polyrhachis cyaneus (worker): TL 9.5 mm, HW 2.08 mm, HL 2.48 mm, CI 84, SL 2.99 mm, SI 144, PSPD 2.63 mm, PPL 1.04 mm, PPW 1.48 mm, PPI 142, PTW 2.55 mm, MTL 2.95 mm. Additional workers (n = 10): TL 7.9–8.9–10.1 mm, HW 1.70–2.01–2.30 mm, HL 2.06–2.36–2.70 mm, CI 79–85–97, SL 2.58–2.88–3.23 mm, SI 132–144–155, PSPD 2.05–2.58–3.13 mm, PPL 0.80–0.98–1.15 mm, PPW 1.05–1.33–1.55 mm, PPI 127–137–151, PTW 2.03–2.37–2.88 mm, MTL 2.55–2.90–3.25 mm.

Head, mesosoma, petiole, and gaster with dark bluish shimmer. Antennae and legs black, except femora bluish; in some specimens tibiae partially reddish brown.

Head sides and dorsum with distinct longitudinal striation overlaying microsculpture, venter with 9–12–15 setae. Vertex with 2–13–20 setae. Frons with 6–9–11 setae, median furrow indistinct. Genae with 0–6–12 setae. Clypeus on disk with 4–13–20 setae.

Dorsal face of mesosoma with 3–36–60 setae, in addition to microsculpture with longitudinal rugae. Pronotal spines gracile and, in cross-section, rather flat (if compared with P. pirata sp. n.), their bases not or indistinctly raised over anterior pronotal disk. Propodeum with dorsal and posterior face separated by almost straight ridge. Sides of mesosoma, in addition to microsculpture, overlaid by longitudinal rugae, on propodeum dorsal of stigma slightly coarser. Femora with 4–13–20 setae, tibiae with 0–1–5 setae.

Gaster with isodiametric reticulum overlaid with fine striation; tergite 1 with 4–25–40 setae, tergite 2 with 12–15–20 setae, following tergites and all sternites with numerous setae increasing in length towards apex of abdomen.

Queen
Sorger and Zettel (2009) - (n = 10): TL 9.4–10.5–10.9 mm, HW 2.00–2.13–2.25 mm, HL 2.38–2.61–2.73 mm, CI 79–82–89, SL 2.76–2.98–3.16 mm, SI 131–140–145, PSPD 2.36–2.62–2.88 mm, PPL 0.75–0.89–1.00 mm, PPW 1.38–1.53–1.65 mm, PPI 152–172–189, PTW 1.98–2.29–2.45 mm, MTL 2.95–3.09–3.23 mm.

Microsculpture on pronotum overlaid with fine striation, on propodeum overlaid with distinctly coarser striation than on pronotum. Gaster punctate, with very fine overlaying striation.

Chaetotaxy: on disk of clypeus 6–13–16, on frons 7–12–14, on vertex 15–20–28, on venter of head 10–13–19, on genae 2–8–14 setae. On dorsum of mesosoma 47–62–72 setae. On femora 12–21–36, on tibiae 1–8–17 setae. On tergite 1 30–41–55, on tergite 2 19– 25–40 setae.

Type Material
Sorger and Zettel (2009) - Holotype of P. cyanea (worker) labelled “Manilla” [Luzon: Manila], “Wthm.”, “Polyrhach.\ cyaneus M.\ det. G. Mayr.”, “Polyrhachis cyanus Mayr.”. In addition, we have seen photographs of the holotype of P. cyaniventris (in ) and can confirm species identity.

References based on Global Ant Biodiversity Informatics

 * Ashmead W. H. 1904. A list of the Hymenoptera of the Philippine Islands, with descriptions of new species. J. N. Y. Entomol. Soc. 12:1-22.
 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * General D. M., and G. D. Alpert. 2012. A synoptic review of the ant genera (Hymenoptera, Formicidae) of the Philippines. Zookeys 200: 1-111.
 * Robson Simon Database Polyrhachis -05 Sept 2014
 * Sorger D. M.; Zettel, H. 2009. Polyrhachis (Myrma) cyaniventris F. Smith, 1858 (Hymenoptera: Formicidae) and a related new ant species from the Philippines. Zootaxa 2174:27-37.
 * Viehmeyer H. 1916. Ameisen von den Philippinen und anderer Herkunft (Hym.). Entomologische Mitteilungen. Berlin-Dahlem 5: 283-291.