Polyrhachis cybele

Polyrhachis cybele is a relatively uncommon species.

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

Kohout (2008) - Polyrhachis aculeata, P. cybele, Polyrhachis gibbosa and Polyrhachis hemiopticoides are all quite similar. The characters separating these four species include the degree to which the posterior blinkers of the eyes are developed, general pilosity and the shape and length of the pronotal and petiolar spines. In P. aculeata and P. hemiopticoides the eyes are strongly truncate and the pronotal and petiolar spines rather long and slender. Polyrhachis aculeata has all the body surfaces covered with numerous, relatively long, erect or semierect hairs and the legs and base of the gaster reddish-brown. In P. hemiopticoides hairs are present only on the head and over the gastral apex, and the gaster and tarsi are black with only the femora and tibiae reddish-brown. Polyrhachis gibbosa differs from both species and also from P. cybele by its distinctly less truncate eyes, stubby body, shorter and thicker petiolar spines and the presence of a distinct pile of short, silvery or whitish, appressed pubescence that is abundant over most of the body surfaces, except the vertex, midline of the mesosoma and gastral dorsum. Polyrhachis gibbosa is apparently limited to Sri Lanka, while P. aculeata and P. hemiopticoides are known from India, with the latter also reported from Laos. Polyrhachis cybele occurs on Borneo, Sumatra and Sulawesi.

Kohout (2013) - The distinguishing characters separating P. cybele from the closely similar species Polyrhachis dimoculata are given in the identification section of that species.

Distribution
Borneo, Sumatra and Java to Sulawesi and the Philippines

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Brunei Darussalam, Indonesia, Malaysia, Philippines.

Nomenclature

 *  cybele. Polyrhachis (Hemioptica) aculeata subsp. cybele Wheeler, W.M. 1919e: 126 (w.) BORNEO. Combination in P. (Myrma): Emery, 1925b: 205. Raised to species: Kohout, 2008a: 271.

Kohout (2013) - Specimens from Sumatra are rather similar to those of the Bornean population, but those from Sulawesi and Java differ in a number of characters. Sulawesi specimens are characterised by a distinctly broader pronotal dorsum and shorter antennal scapes (SI 133-140 versus 144-150 in other populations). In contrast, the single available series of specimens from Java (Kebun Raya, Bogor), differ markedly from other populations by their distinctly more slender body (PW 1.06-1.18 versus 1.22-1.50 in specimens from Borneo, Sumatra and Sulawesi). The Bogor specimens also have the body hairs distinctly less abundant and virtually absent from the antennal scapes, vertex of the head, dorsum of the mesosoma and most of the gastral dorsum, except the apex. However, specimens from across the entire distribution are closely similar in their general appearance and I believe all the examined populations are conspecific.

Worker
Kohout (2013) - Dimensions (syntype cited first): TL c. 7.00, 5.95-7.96; HL 1.68, 1.53-1.87; HW 1.43, 1.28-1.56; CI 85, 75-85; SL 2.09, 1.81-2.28; SI 146, 133-150; PW 1.22, 1.06-1.50; MTL 2.15, 1.96-2.46 (1+25 measured).

Queen
Kohout (2013) - Dimensions: TL c. 8.26; HL 1.84; HW 1.59; CI 86; SL 2.18; SI 137; PW 1.72; MTL 2.34 (1 measured).

Queen larger than worker with usual characters identifying full sexuality, including three ocelli, complete thoracic structure and wings. Pronotal spines distinctly shorter, only marginally longer than their basal width, anteriorly directed. Mesoscutum somewhat wider than long; lateral margins converging anteriorly into smoothly rounded anterior margin; median line distinct; parapsides only weakly raised posteriorly; mesoscutum in profile with widely rounded anterior face and almost flat dorsum posteriorly. Mesoscutellum moderately convex, only marginally elevated above dorsal plane of mesosoma. Propodeal dorsum convex in outline with lateral margins terminating in narrowly rounded, medially continuous ridges that form rather thin, transverse, medially bowed line dividing propodeal dorsum from declivity. Petiole biconvex in profile, dorsolateral spines reduced to rather blunt, wide-based teeth, only marginally longer than acute lateral teeth; dorsal margin very shallowly, medially notched. Rather smooth and highly polished dorsal body surfaces, pilosity, pubescence and colour, very similar to worker.

Type Material
Kohout (2008) - Syntype workers. BORNEO, SARAWAK, Kuching (J. Hewitt), (examined).

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
 * Kohout R. J. 2013. A review of the Polyrhachis aculeata species-group of the subgenus Myrma Billberg (Hymenoptera: Formicidae: Formicinae), with keys and descriptions of new species. Australian Entomologist 40(3): 137-171.
 * Kohout, R. J. 2008. A review of the Polyrhachis ants of Sulawesi with keys and descriptions of new species (Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum 52:255-317.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
 * Robson Simon Ant Collection, 05-Sept-2014
 * Robson Simon Database Polyrhachis -05 Sept 2014
 * Wheeler W. M. 1919. The ants of Borneo. Bulletin of the Museum of Comparative Zoology 63:43-147.