Contrary to the head support hypothesis of pronotal spines in Pheidole majors are the many Pheidole species whose majors exhibit comparably large heads but lack spinescent phenotypes. Moreover, pronotal spines are not observed in other ant lineages with specialized large-headed major workers. For example, both majors and minors of Carebara lack pronotal spines. Paradoxical to the head support hypothesis, pronotal spines occur in Acanthomyrmex minor workers but are lacking in the majors. Comparative studies, such as the one conducted by Paul and Gronenberg examining mandible muscles of ants [ 25 ], are required to further test the head support hypothesis. Future studies would benefit from the sampling of ant taxa both across spinescent and non-spinescent Pheidole lineages, and across other ant lineages with dimorphic worker castes.

These findings, though preliminary, are consistent with the ‘head support hypothesis’ that pronotal spines of Pheidole majors are skeletomuscular adaptations for supporting their disproportionately large heads. Although a more comprehensive comparative study is necessary to rigorously test this hypothesis, these results offer the first alternative to the assumption that the spinescent architecture observed in ants functions primarily as mechanical defense

X-ray micro-ct scans of a Pheidole drogon major worker specimen ( Fig 3 ) and P. viserion ( S8 Vid ) reveal that the many branching muscle fibers of the first thoracic segment extend throughout substantial portions of the pronotal (anterior) spines. The pronotal spines' interior cuticle appear to serve as anchor points for muscles branches that converge anteriorly and connect to the head capsule. In contrast, the pronotal spines of the minor worker are hollow, aside from a few basal fibers ( Fig 4 ). Moreover, the propodeal (posterior) spines of both major and minor worker of P. drogon lack substantial muscle fibers. The same musculature pattern was also observed for the other three species of the P. cervicornis group.

Volumetric surface models of the minor workers of each species ( Fig 1 ) are presented to illustrate the extreme morphologies that have evolved within the Pheidole cervicornis group. Volumetric surface models of the major worker hypostomal bridge are presented to illustrate an important taxonomically and phylogenetically informative character used for diagnosing Pheidole clades ( Fig 2 ). The three-dimensionality of this character is difficult to demonstrate using conventional methods, but is well-illustrated with micro-ct scans. Interactive 3D PDF’s of volumetric surface models were created for all available worker subcastes of the Pheidole cervicornis group species ( Table 2 ).

The Pheidole roosevelti group [ 21 ] also deserves mention here. While its constituent members lack pronotal spines, many of the species have strongly bifurcating propodeal spines that strongly resemble those seen in the cervicornis group, in addition to mesonotal processes. These morphological similarities are entirely convergent, however, as the roosevelti group is only distantly related to the cervicornis group [ 1 , 7 ].

The only Pheidole species outside of the aforementioned groups that has pronotal spines are P. aristotelis Forel and P. hainanensis Chen et al [ 26 , 27 ]. However, the pronotal and propodeal spines of both species are only subequal in length to the eye, and the latter are not bifurcated. Moreover, the major worker lacks distinct pronotal spines.

The bifurca group is reciprocally monophyletic with the cervicornis group, and its constituent species are unsurprisingly most difficult to distinguish from those of the cervicornis group. The bifurca group is sympatric with the cervicornis group (and the quadrispinosa group) in New Guinea. Moreover, the bifurca group is represented by a dizzying number of undescribed species and morphological variation. Based on our preliminary survey of the bifurca group, the major workers are best distinguished from those of the cervicornis group by the (1) shorter pronotal spines, (2) less spinose or lobate mesonotal processes, and (3) smaller size. Additionally, the hypostomal bridge of most (but not all) bifurca group majors have a stout median tooth and either a pair of very weak or absent submedian teeth. However, there is at least one species in which the hypostomal arrangement is similar to that of the cervicornis group species (stout median tooth flanked by a pair of stout submedian teeth). The minor workers of the bifurca group are extremely variable with respect to length and shape of their mesosomal armaments. Some have bifurcating propodeal spines, some have very long pronotal spines, and some have mesonotal processes. None that we have examined, however, possess the combination of all three. Pheidole purpurascens Emery perhaps comes closest to the cervicornis group morphotype, but this species only has angled (versus bifurcate) propodeal spines.

The quadrispinosa group is sympatric with the cervicornis group in New Guinea. In general, quadrispinosa group workers are smaller than those of the cervicornis group, with proportionally shorter limbs. The major workers as distinguished by the (1) lack of a central median hypostomal tooth, (2) coarsely rugoreticulate head sculpture, (3) deeply excavated antennal scrobes, (4) distinctly concave head vertex, and (5) relatively shorter and more triangular pronotal spines. The minor workers are easily distinguished by their smaller size and non-bifurcating propodeal spines (although they can be strongly curved).

All four species within the Pheidole cervicornis group are immediately distinguished from the vast majority of congeners by the presence of extremely long pronotal spines and propodeal spines. The only other Pheidole clades with pronotal spines all occur in the Old World. These include the quadricuspis clade, the quadrispinosa clade and the bifurca clade. The quadricuspis group is restricted to Southeast Asia and does not occur as far east as New Guinea. The major workers are superficially quite similar to those of the cervicornis group, but are distinguished by the (1) lack of a central median hypostomal tooth, (2) coarsely rugoreticulate head sculpture, and (3) shorter, thicker and more abundant pilosity. The minor workers of the quadricuspis group are easily distinguished by the (1) propodeal spines, which are simple and very short (subequal to eye length), and (2) lack of mesonotal spines or lobes.

All known occurrences of species belonging to the Pheidole cervicornis-group are recorded from New Guinea ( Fig 5 ). In addition to the morphological characters common to all Pheidole, the following characters diagnose the worker caste of the P. cervicornis group from those of all other congeners.

Species accounts

Pheidole barumtaun Donisthorpe. (Fig 11)

Pheidole (Pheidolacanthinus) barumtaun Donisthorpe, 1938: 141, figs 1, 2 (s.w.m.). New Guinea [Papua, Jayapura], Cyclops Mountains, Mount Lina, nest in rotten wood, 1070–1370 m, 1936–03 (L.E. Cheesman) [BMNH, 3 syntype majors and 2 syntype minors examined] [28].

= Pheidole (Pheidolacanthinus) sp. 8 [29]

Major worker. HW 2.10–2.25, HL 2.10–2.22, SL 1.10–1.19, FL 1.62–1.78, EL 0.19–0.24, PSL1 0.61–0.74, PSL3 0.66–0.74, PeL 0.59–0.74, PeW 0.17–0.18, PpW 0.52–0.67, CI 99–105, SI 52–55 (n = 5). Uniformly reddish brown or tricolored with head and gaster reddish brown, mesosoma shining yellowish brown. Head square; posterior margin describing a broad and shallow ‘V’. Head strongly convex in lateral view without any impression of the vertex. Posterolateral lobes separated by a deep median impression giving them a strongly convex appearance. Antennal scrobe absent. Antennal scapes long with erect hairs; strongly curved basally to conform to convexity of head. Frontal carina indistinct; blending with parallel carinulae an undistinguished by strength or length. Anterior medial clypeal margin weakly emarginated. Mandible bidentate apically; striations limited to posterolateral portion. Hypostomal bridge with broad, distinct median tooth; submedian teeth of subequal length to median tooth. Clypeus with strong median carina. All dorsal surfaces of head covered by very fine, parallel, non-intersecting carinulae. Spaces between carinulae weakly foveolate. Carinulae arcuate from anterior clypeal border to frons, converging towards median impression of posterolateral lobes. Carinulae of posterolateral lobes distinctly transverse. Corners of posterolateral lobes shining, but covered with very fine carinulae or striae. Mesosoma armed with long strongly produced pronotal spines, mesonotal spines and propodeal spines. Pronotal spines of subequal length as propodeal spines; directed anterolaterally and becoming downcurved apically. Mesonotal spines approximately eye-length, strongly upturned. Propodeal spines relatively straight, directed posterolaterally. Mesosoma mostly smooth and shining with some transverse striae on dorsum. Petiole relatively long, approximately equal in length to propodeal spine. Petiolar node cuneiform with weakly emarginate vertex. Postpetiole approximately equal in height to petiole; in dorsal view strongly transverse with small lateral projections and weakly sculptured. Basal third of first gastral tergite shagreened.

Minor worker. HW 0.69–0.80, HL 0.80–0.90, SL 1.02–1.18, FL 1.22–1.38, EL 0.15–0.16, ML 1.13–1.28, PSL1 0.53–0.66, PSL2 0.44–0.57, PSL3 0.47–0.62, PeL 0.35–0.45, PeW 0.07–0.13, PpW 0.18–0.23, CI 84–90, SI 146–165 (n = 8). Strongly shining, uniformly reddish brown or tricolored with head and gaster reddish brown, mesosoma shining yellowish brown. Head elongate ovoid, strongly tapering behind the eyes to a narrow posterior margin. Nuchal carinae thin but distinct and forming collar around posterodorsal head margin. Antennal scapes with erect hairs, distinctly surpassing posterior head margin. Head completely smooth except for a few arcuate carinulae between the eyes and mandible. Mesosoma with extremely long spines on the pronotum and propodeum, and shorter spines on the mesonotum. Pronotal spines approximately same length as tibiae; directed anterolaterally and becoming downcurved apically. Mesonotal spines approximately eye-length; spinose to weakly lamellate and flattened; directed posterolaterally and straight. Propodeal spines fused basally into thick upright trunk before diverging; strongly bifurcate, directed posterolaterally and becoming downcurved apically. Petiole very elongate. Petiolar node conical.

The major workers of Pheidole barumtaun are separated from those of P. drogon by the fine carinulae that cover the posterolateral lobes. They are separated from P. viserion by the less sculptured gastral tergite, less striate mandibles and more arcuate carinulae of the frons. Both major and minor workers of P. barumtaun are separated from P. viserion by head and gaster color, which are dark brown in the former and clear yellow in the latter. The minor workers are separated from those of P. drogon by the narrower head (CI 84–90 vs. 89–91), longer legs (FL 1.22–1.38 mm vs. 1.07–1.16 mm) and relatively longer antennal scapes (SI 146–165 vs. 135–141).

There are, however, some distinct differences between the type series (Cyclops Mts.) and the material collected by Snelling from the Wapoga River Area. The type series workers, both majors and minors, are distinctly tricolored with dark brown heads and gasters that contrast with a yellowish mesosoma. The Wapoga workers are uniformly dark reddish brown. The type series majors also have downcurved propodeal spines, versus upturned in the Wapago material. However, there are not clear morphometric differences between these populations, and until further evidence is gathered we consider the variation to be infraspecific.

Pheidole barumtaun was named by Donisthorpe after Barumtaun camp where Cheesman made her collection. Among the examined material, workers were collected from the following microhabitats of primary montane forest: under loose bark of log, in and under living bark of recently felled tree, crown of Pandanus, decayed stalk in Pandanus, in leaf litter. Several of these microhabitats suggest the species might nest and forage in vegetation.

Material examined. INDONESIA, Irian Jaya [Papua, Waropen Regency], PT Freeport Concession, -3.14° 136.57°: Wapoga camp, 1998-04-19, 1067m (R.R. Snelling, RRS1998-122); Wapoga camp, 1998-04-21, 1067m (R.R. Snelling, RRS1998-152); Wapoga camp, 1998-04-22, 1067m (R.R. Snelling, RRS1998-160); Wapoga camp, 1998-04-22, 1097m (R.R. Snelling, RRS1998-169); Wapoga camp, 1998-04-24, 1128m (R.R. Snelling, RRS1998-182); Siewa camp, 1998-04-24, 1067m (R.R. Snelling, RRS1998-161); Siewa camp, 1998-04-24, 1128m (R.R. Snelling, RRS1998-184).

Pheidole cervicornis Emery. (Fig 12)

Pheidole cervicornis Emery, 1900: 322, pl. 8, fig 25 (w.) New Guinea, Lemien [= Aitape, Papua New Guinea] (L. Biró) [HNHM, 1 syntype worker examined] [30]. Combination in P. (Pheidolacanthinus): Emery, 1921: 82; Donisthorpe, 1947: 174 [31].

= Pheidole (Pheidolacanthinus) sp. 5 [29]

= Pheidole sp. 1 (det. R.R. Snelling, 2004, New Guinea)

= Pheidole sp. 1 (det. R.R. Snelling, 2007, New Guinea)

Major worker. Unknown

Minor worker. HW 0.58–0.64, HL 0.58–0.67, SL 0.61–0.67, FL 0.67–0.78, EL 0.10–0.11, ML 0.76–0.87, PSL2 0.29–0.37, PSL3 0.38–0.47, PeL 0.11–0.35, PeW 0.07–0.09, PpW 0.14–0.17, CI 94–101, SI 101–112. Most dark reddish brown with basal third of first gastral tergite a strongly contrasting white; at least one population from eastern New Guinea a uniform light reddish brown to dark reddish brown and lacking contrasting white portion of gaster. Head ovoid, approximately as wide as long. Posterior head margin relatively broad and flat to weakly concave. Nuchal carinae not visible in full face view. Antennal scapes with erect hairs, distinctly surpassing posterior head margin. Frontal carinae distinct and extending past eye level. Mesosoma with extremely long spines on the pronotum and propodeum, and shorter spines on the mesonotum. Pronotal armament begins as thick basal trunk that diverges into two long anterolaterally pointed prongs. Mesonotal spines approximately eye-length; directed posterolaterally and upturned. Propodeal spines fused basally into thick upright trunk before diverging; strongly bifurcate. Dorsal surface of propodeal spines modified into elongate, sharply margined concavities. Petiole very elongate. Petiolar node acuminate. Dorsal head surface opaque and strongly sculptured. Crenulated longitudinal rugulae become reticulated towards posterior head margin; interspaces strongly punctured. Mandibles weakly striate. Clypeus sculptured. Promesonotal dorsum with crenulated rugae traversing anterior portion and thick longitudinal rugae covering remaining portion. Waist and gaster entirely smooth and shining.

Relatively short-limbed species.

Pheidole cervicornis, known only from the minor worker subcaste, is the most distinct member of its eponymous group. The minor workers are the only members of the group which have bifurcated pronotal spines. They are also immediately recognizable by the thickly crenulated rugulae on the head and mesosoma. Additionally, the minor worker has a more circular head with a broad, weakly emarginated posterior margin (vs. elongate head with a narrow and flat posterior margin), and all the limbs are relatively shorter. There is some variation in color between specimens collected from western New Guinea (darker and have a contrasting white spot on their gaster), and eastern New Guinea (lighter and lacking white spot). We consider this infraspecific variation until additional collections prove otherwise. Aside from one nest collected from beneath a stone by Wilson (20), Pheidole cervicornis has only been recorded from stray foragers collected from the ground, in leaf litter, on logs, and in logs. It is the most widely collected species of the group, occurring along the northern coast of New Guinea, and also occupies the lowest elevation range (30–800 m). The species also appears to be more tolerant of disturbance than its close relatives, and has been collected in secondary and disturbed forest habitats.

Material examined. INDONESIA, Papua: PT Freeport Concession, Siewa Camp, -3.04° 136.38°, 61m, 1998-04-10 (R.R. Snelling, RRS98-63); PT Freeport Concession, Siewa Camp, -3.04° 136.38°, 61m, 1998-04-15 (R.R. Snelling); 8.1 km ENE Gesa, Gesa river, Mambermo Basin, -2.08° 137.46°, 40m, 2007-05-01 (R.R. Snelling, RRS07-019, RRS07-025, RRS07-026, RRS07-027). PAPUA NEW GUINEA. East Sepik, 3km S. Wewak, -3.61667° 143.61667°, 400m, 1989-02-15 (P.S. Ward, PSW10203-4); Madang, 5km SW Mt. Uluman, Karkar Island, -4.6833° 145.9500°, 800m, 1989-02-05 (P.S. Ward, PSW10142-28); Madang, Ohu village, -5.23333° 145.68333°, 200m, 1999-03-04 (E.M. Sarnat, EMS934); Madang, Ohu village, -5.26° 145.68°, 150m, 2002-01-03 (M. Janda); Madang, Baitabag, -5.143° 145.772°, 30m, 2009-11-14 (M. Janda et al.); Madang, Baitabag, -5.1333° 145.7833°, 50m, 2010-11-03 (M. Janda).

Pheidole drogon Sarnat, Fischer & Economo sp. nov. [urn:lsid:zoobank.org:act:4430D4A8-263C-412A-BAAC-2D989422F363] (Fig 13)

Holotype. Papua New Guinea, Morobe, 11km E Baiyer River Sanctuary, 5.5000° S, 144.2667° E, 1900 m, 24.vi.1980, P. S. Ward, PSW4575-7, montane rainforest, at tuna bait, (major worker, dry pinned, USNM, specimen code CASENT0716380). Paratypes (same data as holotype): 1 minor worker (CASENT0753009, USNM); 2 minor workers, 1 major worker (CASENT0716381, USNM).

= Pheidole sp. EMSM118

= Pheidole sp. EMSM119

Major worker. HW 2.16–2.19, HL 2.08–2.14, SL 1.07–1.08, FL 1.61–1.66, EL 0.18–0.19, ML 1.68, PSL1 0.63–0.70, PSL2 0.61, PeL 0.61–0.64, PeW 0.16–0.17, PpW 0.56–0.58, CI 103–104, SI 49 (n = 2). Color uniformly reddish brown, coxae and legs a weakly contrasting yellowish brown. Head square; posterior margin describing a broad and shallow ‘V’. Head moderately convex in lateral view without any impression of the vertex. Posterolateral lobes separated by a moderate median impression. Antennal scrobe absent. Antennal scapes long with erect hairs; moderately curved basally to conform to convexity of head. Frontal carina indistinct; blending with parallel carinulae an undistinguished by strength or length. Anterior medial clypeal margin weakly emarginated. Mandible bidentate apically; striations restricted to basal portion. Hypostomal bridge with broad, distinct median tooth; submedian teeth of subequal length to median tooth. Clypeus mostly smooth and shining, median carina weak to absent. All surfaces of head covered by fine, parallel, non-intersecting carinulae. Carinulae irregularly longitudinal from anterior clypeal border to frons, diverging weakly towards posterolateral corners and terminating before reaching posterior margin. Posterolateral lobes with smooth and shining corners; lateral and ventral portion of lobes smooth and shining. Mesosoma armed with long strongly produced pronotal spines and propodeal spines; mesonotum armed with broad and flattened lamellate lobes. Pronotal spines of subequal length as propodeal spines; directed anterolaterally and becoming downcurved apically. Propodeal spines relatively straight, directed posterolaterally, becoming weakly downcurved apically. Pronotal dorsum smooth to weakly transversely striate; mesosoma otherwise mostly smooth and shining. Petiole relatively long, approximately equal in length to propodeal spine. Petiolar node cuneiform with weakly emarginate vertex. Postpetiole approximately equal in height to petiole; in dorsal view mostly smooth and shining with several transverse striations on posterior portion and moderate lateral projections. Entire gaster smooth and shining.

Minor worker. HW 0.67–0.73, HL 0.75–0.81, SL 0.94–1.00, FL 1.07–1.16, EL 0.12–0.14, ML 1.06–1.15, PSL1 0.45–0.52, PSL2 0.43–0.49, PSL3 0.36–0.42, PeL 0.35–0.39, PeW 0.07–0.08, PpW 0.15–0.17, CI 89–91, SI 135–141 (n = 8). Strongly shining reddish brown, coxae and legs a weakly contrasting yellowish brown. Head elongate ovoid, tapering weakly behind the eyes to a narrow posterior margin. Nuchal carinae thin but distinct and forming collar around posterodorsal head margin. Antennal scapes with erect hairs, distinctly surpassing posterior head margin. Head completely smooth except for a few arcuate carinulae between the eyes and mandible. Mesosoma with extremely long spines on the pronotum and propodeum, and shorter spines on the mesonotum. Pronotal spines emarginate; approximately same length as tibiae; directed anterolaterally and becoming downcurved apically. Mesonotal spines approximately eye-length; directed posterolaterally and straight. Propodeal spines fused basally into thick upright trunk before diverging; strongly bifurcate, directed posterolaterally and becoming downcurved apically. Petiole very elongate. Petiolar node conical.

The major workers of Pheidole drogon are distinguished from those of all other cervicornis-group species by the posterolateral lobe and gastral tergite, both of which are glossy and free of sculpture or shagreening. The minor workers are difficult to distinguish from those of P. barumtaun, and readers are referred to the discussion of that species for differentiating characteristics. The species is only known from the type locality where it was collected in montane rainforest on low vegetation and also recruiting to a tuna bait.

Etymology: The species name refers to Drogon, the black-colored dragon of Daenerys Targaryen, a fictional character from the George R. R. Martin’s novel A Song of Ice and Fire. The name is a noun in apposition and thus invariable.

Material examined. PAPUA NEW GUINEA, Morobe, 11km E Baiyer River Sanctuary, -5.5000° 144.2667°, 1900 m: 1980-06-23 (P.S. Ward, PSW4528); 1980-06-24 (P.S. Ward, PSW4553-3).

Pheidole viserion Sarnat, Fischer & Economo sp. nov. [urn:lsid:zoobank.org:act:80B52A26-7470-4D15-9A3C-BCCE923FED65] (Fig 14)

Holotype. Papua New Guinea, Southern Highlands, Kutubu area, Mubi River, Kantobo Village, 6.726° S, 143.567° E, 451 m, 9.ii.2008, M. Janda & S. Ibalim, MJ13993, limestone hill (major worker, dry pinned, USNM, specimen code CASENT0219462). Paratypes (same data as holotype): 3 minor workers, USNM (CASENT0282331, CASENT0199517, CASENT0282332).

= Pheidole sp. EPEM109 (nr. barumtaun) [1]

= Pheidole sp. EPEM109 (nr. barumtaun) [8]

= Pheidole sp. PG07 [7]

Major worker. HW 2.09–2.13, HL 2.06–2.11, SL 1.05–1.08, FL 1.60–1.68, EL 0.18–0.20, ML 1.50–1.67, PSL1 0.57–0.68, PSL3 0.70–0.74, PeL 0.59–0.62, PeW 0.14, PpW 0.43–0.46, CI 99–101, SI 50–52 (n = 3). Color uniformly shining yellow, major sometimes with darker yellowish brown head. Head square; posterior margin describing a broad and shallow ‘V’. Head strongly convex in lateral view without any impression of the vertex. Posterolateral lobes separated by a deep median impression giving them a strongly convex appearance. Antennal scrobe absent. Antennal scapes long with erect hairs; strongly curved basally to conform to convexity of head. Frontal carina indistinct; blending with parallel carinulae an undistinguished by strength or length. Anterior medial clypeal margin weakly emarginated. Mandible bidentate apically; entirely striate. Hypostomal bridge with broad, distinct median tooth; submedian teeth of subequal length to median tooth. Clypeus with strong median carina. All surfaces of head covered by fine, parallel, non-intersecting carinulae. Carinulae longitudinal from anterior clypeal border to frons, then diverging laterally and becoming finer. Carinulae of posterolateral lobes arcuate to distinctly transverse. Mesosoma armed with long strongly produced pronotal spines, mesonotal spines and propodeal spines. Pronotal spines of subequal length as propodeal spines; directed anterolaterally and becoming downcurved apically. Mesonotal spines approximately eye-length, strongly upturned. Propodeal spines relatively straight, directed posterolaterally, becoming weakly downcurved apically. Pronotal dorsum transversely striate; mesosoma otherwise mostly smooth and shining. Petiole relatively long, approximately equal in length to propodeal spine. Petiolar node cuneiform with weakly emarginate vertex. Postpetiole approximately equal in height to petiole; in dorsal view strongly transverse with small lateral projections and weakly sculptured. Entire first gastral tergite longitudinally striate.

Minor worker. HW 0.62–0.68, HL 0.75–0.83, SL 1.04–1.12, FL 1.23–1.44, EL 0.12–0.15, ML 1.09–1.24, PSL1 0.53–0.63, PSL2 0.50–0.60, PSL3 0.45–0.60, PeL 0.38–0.44, PeW 0.07–0.10, PpW 0.16–0.19, CI 81–87, SI 162–169 (n = 10). Strongly shining yellow. Head elongate ovoid, tapering behind the eyes to a narrow posterior margin. Nuchal carinae thin but distinct and forming collar around posterodorsal head margin. Antennal scapes with erect hairs, distinctly surpassing posterior head margin. Head completely smooth except for a few arcuate carinulae between the eyes and mandible. Mesosoma with extremely long spines on the pronotum and propodeum, and shorter spines on the mesonotum. Pronotal spines approximately same length as tibiae; directed anterolaterally and becoming downcurved apically. Mesonotal spines approximately eye-length; directed posterolaterally and straight. Propodeal spines fused basally into thick upright trunk before diverging; strongly bifurcate, directed posterolaterally and becoming downcurved apically. Petiole very elongate. Petiolar node conical.

Pheidole viserion is the only member of the cervicornis group that is uniformly yellow in color. The species is most similar to P. barumtaun, but the majors of P. viserion can be distinguished by the more striate mandibles and first gastral tergite, and cephalic sculpture. The minor workers are quite similar to those of P. barumtaun, and are best differentiated by the uniform yellow color.

Pheidole viserion has been collected from three sites in Papua New Guinea from montane primary forests and from a lowland habitat transitioning between primary and secondary forest. In addition to being found in the leaf litter, it was also found foraging in a hollow trunk above the ground.

Etymology: The species name refers to Viserion, the cream and gold colored dragon of Daenerys Targaryen, a fictional character from the George R. R. Martin’s novel A Song of Ice and Fire. The name is a noun in apposition and thus invariable.

Material examined. PAPUA NEW GUINEA. Chimbu, 11 km E Haia airstrip, -6.71667° 145.10000°, 900 m, 1999-02-10 (E.M. Sarnat, EMS687); East Highlands, Simbu, -6.72° 145.09°, 1075 m, 2001 (K. Sagata, EX1P23N28); Morobe, Finisterre Mts., Yawan, Yawan-Ubi-camp, -6.16271° 146.839°, 1600 m, 2010-10-29 (M. Janda MJ13587).