Polyrhachis sukarmani

Polyrhachis sukarmani inhabits lowland evergreen forests. Most specimens were collected using canopy fogging method from high trees (ca. 30 m above ground level), while some were collected from the lower vegetation (1.5–2.0 m above ground level) (Jaitrong et al., 2023). Like most Campomyrma species, P. sukarmani nests in the ground with the type series specimens ‘hand collected from the ground nest’ (Sukarman Sukimin, pers. comm., 2006).

Identification
Kohout (2007) - Polyrhachis sukarmani resembles Polyrhachis creusa Emery from Australia and New Guinea but differs in several characters. In P. sukarmani the central area between the frontal carinae is distinctly wider and the pronotal dorsum, in lateral view, is weakly convex. In dorsal view, the lateral margins of pronotal and mesonotal dorsa strongly converge posteriorly while the lateral margins of propodeal dorsum are subparallel or only weakly convergent. The petiole of P. sukarmani has the lateral spines reduced to blunt angles and the dorsal margin arcuate and entire. In contrast, the central area between frontal carinae in P. creusa is distinctly narrower and the pronotal dorsum in lateral view is rather flat. In dorsal view, the lateral margins of the mesosomal dorsum, including the propodeum, are strongly posteriorly convergent. The petiole of P. creusa has short and acute lateral spines and its dorsal margin is shallowly but distinctly notched medially.

Jaitrong et al. (2023) - Polyrhachis sukarmani is somewhat similar to Polyrhachis reidi from E Malaysia (Borneo, Sabah), both having the dorsum of the head and mesosoma rather regularly, longitudinally striate. However, P. sukarmani can be separated from P. reidi by the following characteristics:
 * body smaller (HL < 1.75 in P. sukarmani versus HL ˃ 2.34 in P. reidi)
 * pronotum in dorsal view distinctly transverse, broader than long (almost as long as broad in P. reidi)
 * propodeal junction right angled (obtuse in P. reidi)

Kohout (2013a) did not place P. sukarmani and P. reidi in any species groups.

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

Nomenclature

 *  sukarmani. Polyrhachis sukarmani Kohout, 2007c: 14, figs. 2, 11, 12 (w.q.) BORNEO.

Type Material

 * Holotype: Worker, EAST MALAYSIA, SABAH, Meliau Range, 05º49’N, 117º07’E, 95m, viii. 2004, Sukarman & Sarina (ITBC-USM 2004 Exp.).
 * Paratypes: data as for holotype (12 workers, 1 queen): 7 paratypes in ; 2 paratypes in ; 1 paratype each in, and.

Worker
Dimensions (holotype cited first): TL c. 6.55, 6.30- 6.80; HL 1.72, 1.56-1.75; HW 1.56, 1.40-1.59; CI 91, 88-91; SL 1.84, 1.68-1.87; SI 118, 117-122; PW1.37, 1.22-1.37; MTL 1.81, 1.55-1.87 (6 measured).

Mandibles with 5 teeth. Anterior clypeal margin widely truncate medially, with truncate portion obtusely angulate. Clypeus in profile almost straight with blunt median carina; basal margin only shallowly impressed, laterally indicated by a clearly defined line breaking sculpturation. Frontal triangle distinct. Frontal carinae sinuate, medially with margins weakly raised, posteriorly somewhat converging; central area wide, very weakly convex medially with frontal furrow rather short and flat. Sides of head in front of eyes weakly convex; behind eyes sides rounding abruptly into medially emarginated occipital margin. Eyes distinctly convex, almost protuberant, in full face view clearly breaking lateral cephalic outline. Ocelli lacking. Mesosomal dorsum with deeply impressed promesonotal suture and metanotal groove. Pronotal dorsum transverse, distinctly wider than long, with distinct median depression anteriorly just behind pronotal collar; humeri armed with obtuse teeth and weakly raised anterior margins; lateral margins weakly rounding into promesonotal suture; mesosomal dorsum with lateral margins strongly converging posteriorly. Propodeal dorsum transverse, lateral margins posteriorly terminating in upturned, inward directed ridges that meet medially and form a continuous transverse carina separating propodeal dorsum from relatively high, virtually vertical declivity. Petiole scale-like, rather slim in profile and narrow in dorsal view; dorsal margin arcuate, obtusely angular laterally. Anterior face of first gastral segment concave, with rather narrow antero-dorsal margin rounding onto dorsum of gaster.

Mandibles finely, mostly longitudinally striate with numerous piliferous pits. Clypeus and central area anteriorly reticulate-punctate; sides of head and vertex distinctly, more-or-less regularly, longitudinally striate. Pronotal and propodeal dorsa rather regularly, longitudinally striate with striae on mesonotum distinctly converging posteriorly; sides of mesosoma and petiole finely reticulate. Gaster very finely shagreened.

Mandibular masticatory borders with numerous curved, golden hairs. Anterior clypeal margin with several long setae medially and fringe of very short setae lining margin laterally. Numerous, medium length, erect hairs on clypeus; several paired, medium length, erect hairs along frontal carinae; one pair of anteriorly directed hairs on vertex. Fore coxae with a few long, somewhat curved hairs on anterior face and several short hairs on posterior face; one or two longer hairs on ventral surfaces of middle and hind coxae, trochanters and femora. Gaster dorsally with only a few medium length hairs lining apical segments; hairs more abundant on gastral venter. Very short, closely appressed, rather diluted pubescence distributed over most of head and gaster.

Black; narrow band at mandibular masticatory border, antennal scapes and legs dark to very dark reddish-brown; funiculi dark brown at their bases, with subsequent segments progressively lighter towards funicular apices; condylae yellow. Ventral gastral apex blotched reddish-brown.

Queen
Dimensions: TL c. 8.52; HL 2.00; HW 1.68; CI 84; SL 2.00; SI 119; PW 1.65; MTL 2.18 (1 measured).

A single queen similar to worker with usual differences indicating caste, including three ocelli and complete thoracic structure. Sculpturation of head and body virtually identical to worker with direction of striae following structural characteristics of fully developed mesosoma. Pilosity and colour identical to that in worker.

Etymology
Named in honour of the collector of the type series, Sukarman Sukimin of the ITBC, Universiti Malaysia Sabah.

References based on Global Ant Biodiversity Informatics

 * Kohout R.J. 2007. A review of the subgenus Polyrhachis (Campomyrma) Wheeler from Borneo with descriptions of new species. Asian Myrmecology 1: 7-17.
 * 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
 * Woodcock P., D. P. Edwards, R. J. Newton, C. Vun Khen, S. H. Bottrell, and K. C. Hamer. 2013. Impacts of Intensive Logging on the Trophic Organisation of Ant Communities in a Biodiversity Hotspot. PLoS ONE 8(4): e60756. doi:10.1371/journal.pone.0060756
 * Woodcock P., D. P. Edwards, T. M. Fayle, R. J. Newton, C. Vun Khen, S. H. Bottrell, and K. C. Hamer. 2011. The conservation value of South East Asia's highly degraded forests: evidence from leaf-litter ants. Phil. Trans. R. Soc. B. 366: 3256-3264.