Polyrhachis pubescens

Polyrhachis pubescens is recorded from India, Myanmar, Thailand and West Malaysia. Only very recently it has been identified from Borneo (Sabah); it was not included by Wheeler (1919) or Kohout (in Pfeiffer et al. 2011) in their lists of Bornean ants (Kohout, 2013).

Identification
A member of the Polyrhachis aculeata species group in the subgenus Myrma

key to Polyrhachis aculeata workers

The specimens from Kinabalu Park in Sabah are very similar to material from continental Malaysia and differ mainly in their marginally larger size (HL >1.68 in Bornean specimens versus <1.68 in continental specimens). The longitudinal body striation is also more distinct, due to the somewhat less abundant silvery pubescence which, in continental specimens, is richer and partly obscures the underlying sculpturation.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Malaysia, Philippines. Oriental Region: India, Thailand. Palaearctic Region: China.

Castes
Males and immature stages in private collection of Fuminori Ito.

Nomenclature

 *  pubescens. Polyrhachis pubescens Mayr, 1879: 657 (w.) INDIA. Combination in Hemioptica: Bingham, 1903: 381; in P. (Myrma): Emery, 1925b: 205; Dorow & Kohout, 1995: 94.

Type Material


Neotype designation. Polyrhachis pubescens was originally described from a single worker collected in ‘Ostindien’. The specimen was presented to Mayr by Prof. Schmidt-Göbel and, like that of Polyrhachis aculeata, the holotype should be lodged in the Mayr collection in Vienna. However, in spite of an extensive search, the specimen cannot be located there or in any other collection examined and is considered lost. To establish the nomenclatural stability of the species, I here designate, in accordance with Article 75.3.5 of the International Code of Zoological Nomenclature (Fourth Edition: 1999), a worker specimen as the neotype of Polyrhachis pubescens Mayr. The specimen was selected from a nest series that also includes queens and a male, with part of the colony donated to, where the neotype has also been deposited. The specimen bears the following label: ‘FI 04-49, Ulu Gombak, W-Malaysia, 15.xii.2004, ITO Fuminori’, plus an additional red label: ‘NEOTYPE, QMT 183497, Polyrhachis pubescens Mayr, 1879, designated by R.J. Kohout, 2013’.

Worker
Kohout (2013): Dimensions: TL c. 6.05-7.31; HL 1.59-1.72; HW 1.22-1.34; CI 75-79; SL 2.00-2.18; SI 156-169; PW 1.18-1.25; MTL 1.96-2.09 (11 measured).

Queen
Kohout (2013): Dimensions: TL c. 7.61-7.71; HL 1.72; HW 1.34-1.37; CI 78-79; SL 2.09; SI 152-156; PW 1.56-1.59; MTL 2.03-2.09 (2 measured).

Queen larger than worker with usual characters identifying full sexuality, including three ocelli, complete thoracic structure and wings. Pronotal spines shorter. Mesoscutum wider than long; lateral margins converging anteriorly into moderately rounded anterior margin; median line distinct, bifurcate anteriorly; parapsides flat, only weakly raised posteriorly; mesoscutum in profile with relatively low anterior face and posteriorly flat dorsum. Mesoscutellum only weakly convex, not elevated above dorsal plane of mesosoma. Propodeal dorsum weakly convex in outline, with lateral margins somewhat angular at midlength and terminating in short ridges that extend medially, forming transverse carina dividing propodeal dorsum from concave declivity. Petiole with dorsal margin convex, dorsolaterally armed on each side with two teeth of virtually equal length. Sculpturation, pilosity, pubescence and colour very similar to worker.