Pheidole knowlesi

Pheidole knowlesi occurs on most of the major Fijian islands, but was not found on Beqa, Lakeba and Moala. It was collected in primary rainforest, bryophyte forest, secondary forest, along the forest edge, and in disturbed habitat, from sifted litter, malaise traps and general hand collection in elevations between 50 and 1300m. Workers of this species were foraging on the ground, on rocks, on bryophyte plants, and the nests were found under rocks, in logs, twigs, in litter deposits on tree trunks, and in fallen ant-plants. (Fisher et al. 2016)

Identification
Fisher et al. (2016) - knowlesi group: Major worker: slightly larger (WL 0.96–1.13mm); head surface shiny with small, superficially punctate spots between rugae on frons and sides, posterolateral lobes smooth; head in profile not or only weakly impressed between frons and posterior head margin and lobes. Minor worker: head dorsum medially smooth with superficial punctures, often with irregular rugulae on frons and slightly reticulate sculpture laterally; promesonotum with weak or faint transverse rugulae dorsally, low in profile with gently sloping posterior declivity. Queen: large (WL 1.64–1.82) with relatively long legs (FI 85–88); clypeus anteriorly with distinct median notch, space between rugae and near posterior head margin usually smooth and posterolateral corners of head without rugae, rugae on scutum not reaching anterior margin or strongly reduced.

The workers of this species are similar to those of Pheidole wilsoni and Pheidole ululevu. The major worker posterolateral head corners are normally smooth with very little sculpture, the dorsal head outline in profile varies from convex to weakly impressed between the frontal area and the posterolateral lobes and between the longitudinal rugae, and at antennal scrobes punctures are either absent or only weakly developed. The extent of frontal carinae and longitudinal rugae reaching towards the posterior head margin seems to be in direct correlation to the size and proportion of the head. Major workers with a higher CI and square head often have longer rugae relative to the size of the head than specimens with a longer, more rectangular head shape. Oftentimes major workers of the former type were collected together with those of the latter type in the same sample and from the same colony. Major workers of P. knowlesi are best separated from the other species by absence of punctures on posterolateral lobes and branching or reticulate rugae between eyes and antennal insertions. The minor workers are best recognized by a low promesonotal profile, the presence of weak or faint longitudinal rugulae on frons and transverse rugulae on dorsal promesonotum and the absence of well-defined punctures on frons and dorsal promesonotum.

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

Worker
Minor

Nomenclature

 *  knowlesi. Pheidole knowlesi Mann, 1921: 436, fig. 13 (s.w.q.) FIJI IS. Senior synonym of extensa: Sarnat & Economo, 2012: 98.
 * extensa. Pheidole knowlesi subsp. extensa Mann, 1921: 438 (s.w.) FIJI IS. Junior synonym of knowlesi: Sarnat & Economo, 2012: 98.

Worker
Fisher et al. (2016) - Major (n = 7): HW 0.91–1.16 (1.08), HL 1.01–1.22 (1.13), SL 0.59–0.68 (0.63), MDL 0.57–0.65 (0.61), EL 0.16–0.18 (0.17), WL 0.96–1.13 (1.04), PNW 0.53–0.60 (0.56), PTL 0.35–0.40 (0.37), PPL 0.17–0.19 (0.18), PTH 0.20–0.23 (0.22), PPH 0.18–0.22 (0.20), PTW 0.15–0.17 (0.17), PPW 0.30–0.35 (0.33), PSL 0.16–0.19 (0.17), MFL 0.75–0.88 (0.81), MTL 0.53–0.64 (0.59), CI 90–97 (95), SI 55–67 (59), MDI 53–63 (56), EI 15–18 (16), FI 70–86 (76), PpI 53–61 (58), LPpI 83–100 (90), DPpI 164–194 (181), PpWI 182–212 (196), PpHI 89–102 (93). Posterior head margin, posterolateral lobes, dorsal postpetiole and gaster glassy smooth. Remainder of head and promesonotum usually with superficial punctures between rugae, but sometimes smooth. Propodeum, katepisternum, anepisternum, and lateral petiole from weakly rugopunctate to superficially punctate with some areas appearing smooth. Head subrectangular, sides convex and curved towards posterior head corners; posteriorly about as wide as anteriorly or slightly narrower. Mandibles and clypeus smooth, anterior margin weakly impressed medially. Antennal socket located in excavated pit, frontal lobes translucent. In profile view dorsal head outline simple and convex, without distinct impression between frons and posterolateral lobes. Hypostomal margin with small median tooth and submedian teeth. Frons and sides of head with well-defined longitudinal rugae. Frontal carina sharply defined and raised, bordering whole length of scrobe, reaching posterior end of scapes when in repose and ca. ¾ towards posterior head margin. Antennal scrobe narrow and often very weakly defined. Antennal scape length more than ½ of head width (SI 55–67), slightly surpassing anterior 2/3 of head, with decumbent pilosity and longer erect hairs along outer edge. Promesonotum in profile convex. Posterior declivity ranging from shallowly oblique to weakly angulate. Metanotal groove narrowly impressed. Propodeum in profile as long as high to slightly longer, spines about as long as distance between their bases. In dorsal view pronotal humeri angulate, but not projecting. Promesonotum with transverse rugulae. Metatibia pilosity mostly decumbent or subdecumbent with long suberect hairs along outer edge. Petiole laterally and ventrally weakly punctate, petiolar dorsum and postpetiole smooth and shiny. Postpetiole with acutely angulate lateral processes, on average 2 times wider than petiole (PpWI 182–212) and 1.8 times wider than long (DPpI 167–194). Standing hairs abundant, mostly erect, long and flexuous, with very fine hairs of medium length and shorter decumbent to subdecumbent pilosity. Color ranging from orange to light brown to darker reddish brown, antennae and legs lighter.

Minor (n = 7): HW 0.50–0.58 (0.53), HL 0.55–0.65 (0.59), SL 0.53–0.62 (0.57), MDL 0.34–0.42 (0.37), EL 0.11–0.13 (0.12), WL 0.67–0.83 (0.74), PNW 0.33–0.40 (0.35), PTL 0.19–0.29 (0.23), PPL 0.11–0.13 (0.12), PTH 0.12–0.15 (0.13), PPH 0.10–0.13 (0.11), PTW 0.09–0.11 (0.10), PPW 0.14–0.18 (0.15), PSL 0.08–0.11 (0.09), MFL 0.54–0.68 (0.60), MTL 0.37–0.50 (0.43), CI 89–96 (91), SI 105–110 (107), MDI 64–72 (68), EI 20–25 (22), FI 105–118 (112), PpI 40–49 (43), LPpI 100–115 (103), DPpI 121–143 (130), PpWI 142–162 (151), PpHI 80–89 (84). Majority of head, mesosoma, and lateral petiole weakly to superficially punctate, often overlain with irregular rugulae. Mandibles, clypeus, posterior head margin, dorsal promesonotum (sometimes), petiolar dorsum, postpetiole and gaster smooth and shiny. Head shape oval to weakly subrectangular, posterior margin widely transverse, sometimes very weakly concave medially, sides convex. Frons partly smooth with relatively long rugula next to short frontal carina. Scapes surpassing posterior head margin by approximately one eye length (SI 105–110), pilosity decumbent to subdecumbent with few suberect hairs along outer edge. Promesonotal outline in profile slightly elongate and flatly convex, with a small process on posterior declivity just anterior of propodeum. Metanotal groove widely impressed, with long, weakly to superficially developed crossribs, interspaces between dorsal cross-ribs smooth and shiny. Propodeum about as high as long, spines relatively long-spinose, almost as long as distance between their bases. Promesonotum dorsally with several short, weakly to faintly developed, transverse rugulae. Metatibia pilosity similar to scape pilosity. Postpetiole on average as long as high (LPpI 100–115), in dorsal view distinctly wider than long (DPpI 121–143). Standing hairs on mesosoma and metasoma not abundant, moderately long, acute, slender, erect to suberect, the two hairs at pronotal humeri very long. Shorter pilosity very fine, subdecumbent to decumbent. Color dark orange to brown, mandibles, antennae, and legs lighter.

Queens
Fisher et al. (2016) - (n = 3): HW1.11–1.21 (1.17), HL 1.05–1.15 (1.10), SL 0.66–0.73 (0.71), MDL 0.63–0.67 (0.65), EL 0.33–0.35 (0.34), WL 1.64–1.82 (1.75), PNW 1.10–1.18 (1.15), PTL 0.55–0.63 (0.58), PPL 0.34–0.35 (0.35), PTH 0.42–0.46 (0.44), PPH 0.41–0.44 (0.42), PTW 0.37–0.43 (0.40), PPW 0.72–0.74 (0.73), PSL 0.29–0.32 (0.30), MFL 0.97–1.06 (1.02), MTL 0.70–0.78 (0.74), CI 104–109 (106), SI 59–61 (60),MDI 54–57 (55), EI 29–30 (29), FI 85–88 (87), PSLI 24–27 (26), LPpI 80–85 (82), DPpI 206–212 (210), PpWI 172–195 (184), PpHI 92–100 (96). Head slightly wider than long (CI 104–109), anterior margin of clypeus with distinct concave median notch. Mandibles laterally near their bases weakly rugulose. Face mostly smooth between rugae, anterolaterally superficially punctate, rugae often ending before reaching posterior head margin, if reaching the posterior margin then without reticulation. Ventral side of head smooth with some superficial rugulae. Scapes moderately short (SI 59–61), pilosity decumbent to subdecumbent with longer erect hairs along outer edge. Eyes moderately large (EI 29–31). Hypostomal margin with relatively small and reduced median tooth and submedian teeth. Oblique carinae on scutum in anterodorsal view not reaching anterior margin and sometimes reduced or inconspicuous. Lateropronotum, posterior half of anepisternum and propodeum finely rugulose, remainder of mesosoma smooth. Petiole ventrally convex, superficially punctate and sometimes with transverse rugae, anterodorsally smooth. Postpetiole in profile with convex, superficially punctate ventral process, in dorsal view smooth, wide (PpWI 172–195), with lateral corners extended into bluntly angulate processes. Gaster smooth. Standing hairs yellow, abundant, moderately long, erect, with shorter suberect pilosity in between. Color reddish brown, with various dark patches on mesosoma, gaster darker, legs and antennae lighter colored.

Type Material
Fisher et al. (2016) - FIJI, Vanua Levu, Suene; major worker, minor worker, queen described (, examined).

References based on Global Ant Biodiversity Informatics

 * Dlussky G.M. 1994. Zoogeography of southwestern Oceania. Zhivotnoe naselenie ostrovov Iugo-Zapadnoi Okeanii ekologo-geograficheskie issledovanii 48-93.
 * Fischer G., E. M. Sarnat, and E. P. Economo. 2016. Revision and microtomography of the Pheidole knowlesi Group, an endemic ant radiation in Fiji (Hymenoptera, Formicidae, Myrmicinae). PLoS ONE 11(7): e0158544. doi:10.1371/journal.pone.0158544
 * Mann W. M. 1920. Ant guests from Fiji and the British Solomon Islands. Annals of the Entomological Society of America 13: 60-69.
 * Mann W. M. 1921. The ants of the Fiji Islands. Bull. Mus. Comp. Zool. 64: 401-499.
 * Sarnat Eli M. 2009. The Ants [Hymenoptera: Formicdiae] of Fiji: Systematics, Biogeography and Conservation of an Island Arc Fauna. 80-252
 * Ward, Darren F. and James K. Wetterer. 2006. Checklist of the Ants of Fiji. Fiji Arthropods III 85: 23-47.
 * Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
 * Wheeler, William Morton.1935.Checklist of the Ants of Oceania.Occasional Papers 11(11): 3-56
 * Wilson E.O., and G.L. Hunt. 1967. Ant fauna of Futuna and Wallis islands, stepping stones to Polynesia. Pacific Insects 9(4): 563-584.
 * Wilson, Edward O. and George L. Hunt. 1967. Ant Fauna of Futuna and Wallis Islands, Stepping Stones To Polynesia. Pacific Insects. 9(4):563-584.
 * Wilson, Edward O. and Hunt, George L. Jr. 1967. Ant Fauna of Futuna and Wallis Islands, Stepping Stones to Polynesia. Pacific Insects. 9(4):563-584