Polyrhachis rufofemorata

Polyrhachis rufofemorata is lignicolous, selecting various plant cavities for its nesting sites, with most colonies found occupying hollow internodes of standing dead bamboo.

Identification
As indicated by Kohout (1989, 1998), P. rufofemorata appears in two distinct forms that differ primarily in the development of the petiolar node. In the nominal form, including most of its synonyms (P. merops Fr. Smith, 1860, P. biroi Forel, 1907 and P. biroi paprika Forel, 1911), the petiole is simply angulate or at most minutely dentate, while it is clearly spinose in P. biroi bidentata. Both forms are relatively common throughout New Guinea and are occasionally sympatric. However, it appears that Indonesian populations of P. rufofemorata include only the nominal form, while Australian populations are characterised by the distinctly spinose petiole. Queens of both forms are very similar with only a little variability demonstrated between various populations.

Distribution
The known distribution of P. rufofemorata extends from the Moluccas and New Guinea to northern Australia, where it occurs at Iron Range on Cape York Peninsula (Kohout, 2012).

This taxon was described from Indonesia (Aru Island).

Castes
Males and immature stages are present in the ANlC and RJK spirit collections.

Nomenclature

 *  rufofemorata. Polyrhachis rufofemoratus Smith, F. 1859a: 142 (w.) INDONESIA (Aru I.). Kohout, 1989: 514 (w.q.). Combination in P. (Myrma): Emery, 1925b: 202. Senior synonym of merops: Bolton, 1974b: 178; of bidentata, biroi, paprika: Kohout, 1998: 523. Current subspecies: nominal plus atra.
 * merops. Polyrhachis merops Smith, F. 1860b: 98, pl. 1, fig. 17 (w.) INDONESIA (Batjan I.). Combination in P. (Myrma): Emery, 1925b: 202. Subspecies of rufofemorata: Emery, 1898a: 228; Donisthorpe, 1932c: 460. Junior synonym of rufofemorata: Bolton, 1974b: 178.
 * biroi. Polyrhachis biroi Forel, 1907a: 40 (w.) INDONESIA (Ambon I.). Combination in P. (Myrma): Emery, 1925b: 200. Junior synonym of rufofemorata: Kohout, 1998: 523.
 * paprika. Polyrhachis biroi var. paprika Forel, 1911e: 296 (w.) NEW GUINEA. Combination in P. (Myrma): Emery, 1925b: 200. Junior synonym of rufofemorata: Kohout, 1998: 523.
 * bidentata. Polyrhachis biroi var. bidentata Stitz, 1912: 512 (w.) NEW GUINEA. Combination in P. (Myrma): Emery, 1925b: 200. Junior synonym of rufofemorata: Kohout, 1998: 523.

Polyrhachis rufofemoratus type material.

Holotype worker from Aru Island, Indonesia (A.R. Wallace) (examined by Kohout, 2012).

Polyrhachis biroi bidentata type material.

Syntype workers from Sattelberg, New Guinea (Lauterbach) (examined by Kohout, 2012).

Type Material


Polyrhachis merops

Holotype worker in. Labelled “Bac.” (= Batjan I.) and with a Donisthorpe type-label.

Polyrhachis rufofemoratus

Holotype worker in. Labelled “Aru 7” (= Aru I., New Guinea) and with a Donisthorpe type-label.

Additional specimens are present in, from “Ceram” (= Seram I.), “Wag.” (= Waigeo I.) and “Gor.” (=?).

Worker
Kohout (1989) - Dimensions: TL 8.47-9.58; HL 2.27-2.53; HW 1.62-1.84; CI 71-77; SL 2.71-3.02; SI 154-170; PW 1.03-1.31; MTL 3.02-3.48 (35 measured).

Mandibles with 5 teeth. Clypeus sinuate in profile, convex above, concave below; median carina more or less distinct; anterior margin truncated medially. Sides of head in front of eyes only feebly convex (almost straight in some specimens), slightly converging anteriorly; behind the eyes broadly convex. Eyes convex, in full face view not or only marginally breaking the outline of the head. Median ocellus weakly marked in some specimens. Frontal carinae sinuate with sharply raised lobes. Pronotum with a pair of long, divergent, somewhat flattened spines; their outer borders continuous, with posteriorly diverging lateral margins. Mesonotal dorsum wider than pronotum at the base, transversely convex, lateral margins acute but not laminate. Propodeal dorsum deeply concave between lateral margins, which form almost vertically raised lamellate flanges; posterior angles rounded, not acute. Petiole scale-like. with dorsal edge usually angulate or dentate, but also distinctly spinose, as in some New Guinean and all known Australian populations. Base of first gastral tergite very shallowly concave.

Mandibles finely longitudinally striate, with numerous piliferous pits. Anterior c1ypeal margin medially with a row of distinct pits from which long hairs arise. Sculpturation of the head and mesosoma consisting of fine to coarse reticulations, with dorsum of the head more or less longitudinally striate. Intensity of the sculpturation decreasing posteriorly, the petiole and gaster finely shagreened.

Short to medium long, semierect, yellow to rusty-brown hairs scattered all over the body. Short appressed pubescence of variable density everywhere, but almost absent from the petiole and the base of the first gastral tergite; colour of the pubescence yellow with distinct reddish tint on dorsum of head, -mesosoma and gaster, more silvery on lateral and ventral surfaces of the body and appendages.

Body distinctly bicoloured; black, with the petiole, base of the first gastral tergite, coxae and femora, save for their apical portions, light to medium reddish-brown. Tips of the petiolar spines or dentic1es also black.

Queen
Kohout (1989) - Dimensions: TL 9.42-10.43; HL 2.37-2.59; HW 1.68-1.89; CI 70-75; SL 2.77-3.02; SI 154-168; PW 1.61-1.91; MTL 3.17-3.53 (14 measured).

Female larger, with the usual characters identifying full sexuality. The sculpturation, pubescence and coloration is similar to that of the worker. Eyes convex, usually breaking the outline of the head. Configuration of the petiolar spines cute teeth, situated along the dorsal edge of the segment between the distinct lateral angles.

Additional References

 * 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 – Nature 56(1): 25-59.