Polyrhachis (Myrma) pirata, Sorger, D. M. & Zettel, H., 2009

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, pp. 27-37 : 33-36

Polyrhachis (Myrma) pirata sp. n.

(Figs 7-10, 12)

Etymology: Latin for "pirate," used as a noun in apposition. The name pirata is an homage to the mythic world of ancient pirates. The stoutness, distinct colours and massive spines of this species - in comparison to related species - served as an inspiration for this name.

Type locality: Philippines, Luzon Island, Quezon Province, Quezon National Park near Atimonan, dipterocarp forest near Old Zigzag Road.

Type material: Holotype (worker) labelled " Philippinen: Luzon , Quezon \ Atimonan , Quezon NP \ Old Zigzag Rd. , 24.-30.3.\ 1998, leg. Zettel ( #165 )" ( UPLB). Paratypes: Luzon Isl. : Zambales Prov. [erroneously labelled " Bataan "]: Olongapo , Subic Bay , " Jungle Educational Survival Training" area , 4.XII.1993, leg. H. Zettel ( #37h ), 1 worker ( NHMW). Quezon Prov. : Atimonan , Quezon National Park , Old Zigzag Road , 24.- 30.III.1998, leg. H. Zettel ( #165 ), 31 workers ( CZW, CSW, NHMW, QMBA, UPLB, USC-EC), 16.III.1999, leg. H. Zettel ( #202 ), 2 workers ( NHMW). Camarines Norte Prov. : Labo , Tulay na Lupa , Mt. Labo - Mt. Bayabas area, 17.-18.III.2004, leg. H. Zettel & C. V. Pangantihon ( #382 ), 1 worker (CZW). Mindoro Isl. : Occidental Mindoro : [ San Jose ,] Mangarin , 12.[19?]17, unknown collector, 1 worker (MCZL). Samar Isl. : Northern Samar Prov. : San Joaquin , Lologayan Falls , 4.-6.III.2003, leg. H. Zettel ( #345 ), 1 worker ( CZW), 1.- 5.III.2004, leg. H. Zettel ( #377 ), 9 workers ( CZW, NHMW, UPLB).

Additional material (not examined): G. Alpert (in litt.) reported four workers from Luzon Island held in the Museum of Comparative Zoology, Cambridge, U.S.A.: Zarnbales Prov., no further data, leg. Baker (gift of W.M. Wheeler), 1 worker; Laguna Prov.: Pakil, Saray [labelled "Paeta, Sarai"], leg. McGregor, 1 worker; Mt. Makiling, low altidute, leg. F.X. Williams (gift of W.M. Wheeler), 2 workers.

Description of worker: Measurements: Holotype worker: TL 10.8 mm, HW 2.33 mm, HL 2.83 mm, CI 82, SL 3.33 mm, SI 143, PSPD 3.28 mm, PPL 1.34 mm, PPW 1.71 mm, PPI 128, PTW 3.00 mm, MTL 3.66 mm. Paratype workers (n = 10): TL 10.1-10.8-11.5 mm, HW 2.19-2.37-2.50 mm, HL 2.60-2.83-2.98 mm, CI 81-84-86, SL 3.15-3.34-3.50 mm, SI 130-141-146, PSPD 2.90-3.19-3.50 mm, PPL 1.23-1.38-1.49 mm, PPW 1.49-1.75-1.94 mm, PPI 114-127-137, PTW 2.49-2.93-3.23 mm, MTL 3.18-3.47-3.64 mm.

Head and mesosoma with bluish green, in some specimens slightly coppery shimmer; petiole and gaster often appearing darker and more bluish than mesosoma. Antennae and legs (except femora) black.

Head dorsum with some fine rugae between eyes, sides without rugae. Venter without setae. Vertex usually without setae (except in one specimen with two setae). Frons with fine median furrow and 4-7 setae. Genae without setae. Clypeus on disk with 5-7 setae.

Mesosoma dorsally without setae; in addition to microsculpture on disk of pronotum and - more distinct - on propodeum with very fine longitudinal rugae. Pronotal spines long and massive, in cross-section approximately triangular, their bases conspicuously elevated over anterior pronotal disk (Figs 8, 10). Ridge separating dorsal and posterior face of propodeum sinuate, medially slightly depressed (Figs 9, 10). Sides of propodeum dorsal of stigma with strong longitudinal rugae overlaying microsculpture (Fig 8). Femora and tibiae without setae.

Sculpture of gaster with isodiametric reticulum; tergite 1 without setae, tergite 2 usually without setae (except in five specimens with few setae at hind margin), following tergites and all sternites with numerous setae increasing in length towards apex of abdomen (Fig. 8).

Notes: Some intraspecific variation has been observed in P pirata sp. n.: Compared with specimens from Luzon, the ants from Northern Samar are smaller, appear more gracile, and have a distinctly more bluish shimmer on gaster.

Distribution: Central and Southern Luzon, Mindoro and Samar (Fig 12).

Biology: Habitats are very similar to those of P. cyaniventris and syntopic occurrence was observed in the Quezon National Park and in an abandoned coconut grove in Northern Samar.. However, based on its infrequent occurrence relative to P. cyaniventris and the habitats where it has been found, P. pirata sp. n. probably prefers more natural habitats with higher tree coverage and is possibly restricted to lower altitudes. Although the majority of specimens (Zettel collection #165) were collected on the ground, other individual workers were found foraging on leaves and twigs of small trees and bushes. Nesting habits of P pirata sp. n. are unknown.