Pheidole gatesi (Wheeler)

Eguchi, K., 2008, A revision of Northern Vietnamese species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae)., Zootaxa 1902, pp. 1-118 : 37-40

Pheidole gatesi (Wheeler)

Figs. 9a-g

Aphaenogaster (Attomyrma) gatesi Wheeler , 1927a: 44. Syntypes: 2 minors, "Rangoon, Burma, G.E. Gates" [Myanmar], MCZC cotype-20600, examined.

Pheidole gatesi (Wheeler) . Brown 1966: 283 (combination in Pheidole ), Yamane et al. 2003: 57 (checklist), Eguchi 2003: 323 (description of male), Eguchi, Bui et al. 2005: 89 (checklist).

Other material examined: S. China: Hainan: Wuzhishan N.R., Qiongzhong [J. Fellowes]. Vietnam: Vinh Phuc: Tam Dao N.P., 21°27'N, 105°38'E, 900 m alt. [Eg01-VN-102], Tam Dao N.P., 900-1100 m alt. [Eg99- VN-046, -047, -050, -051], Tam Dao N.P., 900-1240 m alt. [VN98-SKY-07, -22; VN98-HO-008], Tam Dao N.P., 1000 m alt. [Eg01-VN-120], Tam Dao, 1000-1240 m alt. [Sk. Yamane]; Ha Tay (mislabeled as Ha Tai): Ba Vi N.P., 21°03'N, 105°22'E, 800 m alt. [Eg02-VN-046]; Ninh Binh: Cuc Phuong N.P., 20°14'N, 105°36'E [Eg10vi05-02; Eg14vi05-10], Cuc Phuong, 320 m alt. [Eg01-VN-184]. Thailand: Chiang Mai: Doi SuthepPui N.P. [Sk. Yamane; F. Yamane], Doi Suthep-Pui, 900 m alt. [Eg01-TH-081], Doi Suthep-Pui, 1200 m alt. [Eg01-TH-112, -114, -116], Doi Suthep-Pui, 1400 m alt. [TH98-SKY-01], Doi Suthep-Pui, 1470 m alt. [W.L. Brown & I. Burikam, MCZC]. Myanmar: Chin: between Kampetlet and Natmataung N.P., 1373 m alt. [MM02-SKY-37].

Worker measurements & indices: Major (n=5). - HL 2.93-3.40 mm; HW 2.73-3.08 mm; CI 90-100; SL 1.42-1.57 mm; SI 47-58; FL 2.14-2.30 mm; FI 70-84.

Minor (n=5). - HL 0.99-1.11 mm; HW 0.89-1.00 mm; CI 89-94; SL 1.09-1.40 mm; SI 121-144; FL 1.31-1.70 mm; FI 146-173.

Worker description

Major. - Head in lateral view not impressed on vertex; frons and vertex rugose longitudinally-obliquely; dorsum of vertexal lobe rugose or rugoso-recticulate; clypeus with a weak to conspicuous median longitudinal carina; frontal carina and antennal scrobe absent; median process of hypostoma low (but rarely almost absent), sometimes with a concavity in the center; submedian processes low or relatively well developed (but rarely almost absent); lateral processes always present but usually small; antenna with a 4-segmented club; maximal diameter of eye much longer than antennal segment X. Promesonotal dome in dorsal view sparsely and transversely rugose (but rarely with the posterior part rugose irregularly or longitudinally), in lateral view with a small to conspicuous prominence on its posterior slope (but rarely without a prominence/mound); humerus not produced laterad; the dome narrower at the humeri than at the bottom. Petiole almost as long as, or a little longer than postpetiole (excluding helcium); postpetiole relatively large to massive. First gastral tergite weakly rugoso-punctate around its articulation with postpetiole and shagreened in the remainder part (but rarely longitudinally rugose entirely).

Minor. - Dorsum of head smooth, with several rugulae on the area between antennal insertion and eye (rarely rugoso-punctate on the dorsolateral face); preoccipital carina conspicuous dorsally and laterally; median part of clypeus almost smooth, with a weak or conspicuous median longitudinal carina; antenna with a 4-segmented club; scape extending far beyond posterolateral margin of head; maximal diameter of eye almost as long as or shorter than antennal segment X. Promesonotal dome largely smooth, sometimes with weak transverse rugulae dorsolaterally, in lateral view with a conspicuous prominence/mound on its posterior slope; the prominence often developed well as a transverse ridge; humerus of the dome in dorso-oblique view not produced laterad; mesopleuron, metapleuron and lateral face of propodeum punctured weakly, often overlain with weak rugoso-reticulation. Petiole almost as long as or a little shorter than postpetiole (excluding helcium); postpetiole relatively massive.

Recognition: Pheidole gatesi and P. smythiesii are morphologically very similar to each other. Differences between the two species are as follows: in the minor petiole usually 0.85-1.0 times as long as postpetiole in P. gatesi , but usually less than 0.85 times in P. smythiesii ; in the minor dorsum of promesonotum bearing hairs more densely in P. gatesi than in P. smythiesii . Furthermore, in the minor of P. gatesi , the prominence on the posterior slope of promesonotal dome is rather conspicuous, often developed well as a transverse ridge. These differences between the two species are relatively conspicuous when sympatric populations of the two species are compared.

Distribution & bionomics: Known from N. Vietnam, S. China, Thailand and Myanmar. This species inhabits woody habitats, and nests in the soil. Majors serve as repletes (e.g., Eg01-TH-116, Eg01-VN-184, Eg02-VN-046).