Polyrhachis dahlii

As noted by Mann (1919), P. dahlii appears to be a relatively rare species, with its distribution centred on the Bismarck Archipelago. However, there are a few records of the species from New Britain (Gazelle Peninsula, Vunakanau, 11-20.v.1955; Kerevat, 2.ix.1955; Baining Mts, St Pauls, 4.ix.1955 – all J.L. Gressitt), and from the Solomons (San Christoval, Wainoni Bay; Three Sisters, Malapaina; Malaita, Auki; Florida, Tulagi – all W.M. Mann; Guadalcanal, Honiara, 13-16.xi.1953, J.D. Bradley). (Modified from Kohout, 2012.)

Identification
Kohout (1998) suggested Polyrhachis dahli unisculpta to be a junior synonym of Polyrhachis queenslandica and, consequently, a separate taxon from P. dahlii. To verify the identity of the three names, Kohout (2012) directly compared the syntypes of all taxa and confirmed that P. queenslandica and P. dahli unisculpta are undoubtedly conspecific and P. dahlii is a distinct species. The most obvious character separating P. dahlii from P. queenslandica is colour which, in the former, is yellow or very light yellowish brown with only the mandibular teeth, anterior clypeal margin, frontal carina and the lateral margins of pronotum and mesonotum narrowly bordered with brown. In contrast, P. queenslandica is virtually black or dark reddish-brown with the head a shade darker. The sculpturation of the head and mesosoma in P. dahlii is rather coarsely reticulate-punctate, while it is distinctly finer in P. queenslandica. The gaster in both species is very finely shagreened and highly polished. (Modified from Kohout, 2012.)

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea, Solomon Islands.

Nomenclature

 *  dahlii. Polyrhachis dahlii Forel, 1901b: 30 (w.) NEW GUINEA (Bismarck Archipelago). Combination in P. (Myrmothrinax): Mann, 1919: 378. See also: Kohout, 2012: 35.

Syntype workers from Ralum, Bismarch Archipelago, 17.iii.97 (F. Dahl) (examined by Kohout, 2012).

References based on Global Ant Biodiversity Informatics

 * 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
 * Dahl F. 1901. Das Leben der Ameisen im Bismarck-Archipel, nach eigenen Beobachtungen vergleichend dargestellt. Mitt. Zool. Mus. Berl. 2: 1-70.
 * Forel A. 1901. Formiciden aus dem Bismarck-Archipel, auf Grundlage des von Prof. Dr. F. Dahl gesammelten Materials. Mitt. Zool. Mus. Berl. 2: 4-37.
 * Janda M., G. D. Alpert, M. L. Borowiec, E. P. Economo, P. Klimes, E. Sarnat, and S. O. Shattuck. 2011. Cheklist of ants described and recorded from New Guinea and associated islands. Available on http://www.newguineants.org/. Accessed on 24th Feb. 2011.
 * Kohout R. J. 2012. A review of the Australian Polyrhachis ants of the subgenera Myrma Billberg, Myrmatopa Forel, Myrmothrinax Forel and Polyrhachis Fr. Smith (Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum 56(1): 25-59.
 * Mann W. M. 1919. The ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology 63:273-391.
 * Mann William. 1916. The Ants of the British Solomon Islands. Bulletin of the Museum of Comparative Zoology at Harvard College 63(7): 273-391
 * Robson Simon Database Polyrhachis -05 Sept 2014
 * Viehmeyer H. 1912. Ameisen aus Deutsch Neuguinea gesammelt von Dr. O. Schlaginhaufen. Nebst einem Verzeichnisse der papuanischen Arten. Abhandlungen und Berichte des Königlichen Zoologischen und Anthropologische-Ethnographischen Museums zu Dresden 14: 1-26.
 * Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
 * Wheeler, William Morton.1935.Checklist of the Ants of Oceania.Occasional Papers 11(11): 3-56