Eurhopalothrix cinnamea

The type series (eight workers) was collected from a Berlese funnel sample of leafmould taken from primary tropical rain forest.

Identification
Taylor (1990) - This species is not especially striking or unusual. It clearly belongs in the group of E. procera (Taylor 1968), and appears to be part of a Melanesian radiation from procera-like stock, which also includes the Solomon Islands species Eurhopalothrix greensladei and Eurhopalothrix isabellae.

E. cinnamea runs to E. isabellae in couplet 3 of my 1968 key to the IndoAustralian Basicerotini. These species may be differentiated by inserting the following couplet 3a into the key:

Propodeal teeth well developed, supporting broad infra-dental lamellae, a triangular area of propodeal dorsum anterior to their bases distinctly concave, and more or less clearly set off from the remaining dorsum. Colour medium-dark reddish brown (Solomon Islands: Ysabel and Vella Lavella) E. isabellae

Propodeal teeth vestigial, surmounting very narrow infradental lamellae. Propodeal dorsum almost entirely convex, with at most only slight traces of a posteromedian concavity. Colour bright golden chestnut brown (Manus Island) E. cinnamea

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

Nomenclature

 *  cinnamea. Eurhopalothrix cinnamea Taylor, 1970a: 50, figs. 1-4 (w.) NEW GUINEA (Bismarck Archipelago).

Worker
Dimensions as follows (holotype cited first): TL c. 3.3, 3.2-3.5 mm; HL 0.73, 0.73-0.77 mm; HW 0.77, 0.76-0.82 mm; CI 105, 104-107; ML 0.20, 0.20-0.21 mm; MI 27, 26-27; SL 0.45, 0.44-0.48 mm; SI 58, 56-59; greatest diameter of eye 0.08, 0.08-0.09 mm; PW 0.48, 0.47-0.51 mm; WL 0.89, 0.89-0.95 mm; petiolar node width 0.20, 0.20-0.21 mm; postpetiole width 0.45, 0.45-0.47 mm; maximum gastral width 0.63, 0.63-0.66 mm. General features as shown in accompanying figures. Frons moderately inflated. Mandibular structure and dentition much as in Eurhopalothrix isabellae: outer borders concave (less strongly than in isabellae); posterior borders oblique, framing (with the anterior clypeal border) a narrow, roughly triangular gap when the jaws are closed; basal teeth broad, blade-like, each about twice as wide at base as the conical more apical teeth. Promesonotum strongly inflated; dorsum much higher than propodeum, almost entirely convex, with only very slight traces of a median longitudinal depression and bilateral tumosities; humeri broadly rounded in dorsal view. Promesonotal sulcus virtually obsolete above anterior spiracles. Mesometanotal suture not incised or otherwise differentiated in angle formed at promesonotal-propodeal junction. Propodeal teeth barely developed, represented only as small obtuse dorsal angles to low lamellae which border the declivity laterally. Outline oflamellar crests simple, approximately parallelling face of declivity. A very fine trans-dental carina crosses the propodeum between the dorsal lamellar angles. Propodeal dorsum anterior to this carina more or less evenly convex, not invaded from behind by a distinct concave triangular extension of the declivity, as in Eurhopalothrix procera, Eurhopalothrix greensladei, and isabellae. Subpetiolar process with traces of serrations, probably homologous with those of E. procera. Dorsum of petiolar node minutely broader than long. Postpetiole about t as long as wide; posterodorsal tumosities moderately developed. Gaster about 1.4 x wider than postpetiole.

Mandibles finely, obscurely granulose-punctate, especially near bases. Clypeus, frontal carinae, and most of frons, closely, moderately coarsely, but shallowly punctate; a depressed triangular area between frontal carinae obscurely and very finely shagreened; similar microsculpture overlying and partly obscuring frontal puncturation, especially postero-medially. Occiput, anterior to occipital carina, moderately finely and distinctly punctate; area behind carina, postgenae and antennal foveae finely and distinctly granulose-punctate. Scapes sculptured like mandibular bases. Promesonotal dorsum moderately coarsely but shallowly punctate-rugose, with a more or less longitudinal bias, especially posteriorly. Propodeal dorsum similarly but much more finely sculptured; declivity, below trans-dental carina, textured like antennal foveae. Sides of mesosoma, coxae, petiole, postpetiole and first gastral sternite densely and sharply punctuate; average punctural diameter about 0.01-0.015 mm, interpunctural distances averaging c. H diameter of surrounding punctures; puncturation roughened and effaced on dorsa of petiole and postpetiolar tumosities, less strongly incised on gaster than elsewhere. Median strip of first gastral tergite with moderately dense, slightly effaced, medium puncturation, grading outwards to smooth, shining lateral areas. Legs, distal to coxae, very finely and densely granulose-punctate.

Ground pilosity of minute bristle-like hairs about 0.0 I mm long, extremely reduced and sparse where present; virtually absent on head except outer crests of occipital lobes and around eyes; elsewhere noticeably developed only on dorsa of promesonotum, petiole and postpetiole. Face of scape moderately covered by longer (c. 0.03 mm) narrowly clavate hairs; its outer edge with about 10 erect, narrowly clavate hairs, grading distally from c. 0.08-c. 0.04 mm long. A few similar hairs on apex of gaster and posterior area of its first sternite. Legs, proximal to femoral apices, with dense small hairs like those on face of scape; tibiae and tarsi with similarly dense but broad flattened hairs about 0.03 mm long and 0.02 mm wide. A pair of narrowly clavate erect specialised hairs c. 0.1 mm long on frons. Pubescence noticeable only on antennal scapes. General colour of head, body and appendages even, rich, golden chestnut brown; pilosity and pubescence yellowish-white.

Type Material
Bismarck Archipelago (Admiralty Group): Manus Island: Lorengau (22.vi.l962, "Noona Dan" Expedition; No. 13 cd. hr 71). The type series (eight workers) was collected in a Berlese funnel sample of leafmould from primary tropical rain forest near the expedition campsite about 4 km SW of Lorengau (Petersen 1966). Holotype and four paratypes in Universitets Zoologiske Museum, Copenhagen; two paratypes in, one paratype in.

References based on Global Ant Biodiversity Informatics

 * 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.
 * Taylor R. W. 1970. Notes on some Australian and Melanesian basicerotine ants (Hymenoptera: Formicidae). Journal of the Australian Entomological Society 9: 49-52.