Pheidole dugasi

This species usually nests under the ground in woody gardens and forest edges. Majors serve as repletes (e.g., Eg01-TH-034, -142) (Eguchi 2008). In S. Cat Tien N.P. (S. Vietnam) I observed masses of workers retrieving seeds from mammal feces. (Eguchi 2008)

Identification
Eguchi (2008) - This species is characterized among Indo-Chinese species by the combination of the following characteristics:
 * in the major and minor body extremely large
 * in the major frons with longitudinal-oblique rugulae which run till the end of vertexal lobes
 * in the major and minor antennal club 3-segmented

In N. Vietnam there are two other extremely large-sized species, Pheidole gatesi and Pheidole smythiesii. But these two species are easily separated from P. dugasi by the 4-segmented antennal club in the major and minor. Pheidole magna Eguchi (see below) is relatively similar to P. dugasi, but easily separated from P. dugasi by the following characteristics of the major of P. magna: dorsal and lateral faces of vertexal lobe smooth and shining; first gastral tergite smooth and shining, often with a weakly punctured area just around its articulation with postpetiole (see also Eguchi 2006).

Distribution
Known from Vietnam, S. China and Thailand.

Distribution based on Regional Taxon Lists
Oriental Region: Laos, Thailand, Vietnam. Palaearctic Region: China.

Nomenclature

 *  dugasi. Pheidole dugasi Forel, 1911i: 222 (footnote) (w.) VIETNAM. See also: Eguchi, 2008: 17.

Worker
Eguchi (2008) - Major (n=5). — HL 3.38–3.60 mm; HW 3.15–3.40 mm; CI 93–99; SL 1.48–1.67 mm; SI 47–49; FL 2.35–2.49 mm; FI 71–78. Minor (n=5). — HL 0.97–1.19 mm; HW 0.84–1.04 mm; CI 85–88; SL1.15–1.36 mm; SI 124–137; FL 1.47–1.67 mm; FI 159–175.

Major — Head in lateral view roundly convex dorsally, not impressed on vertex; frons with longitudinal-oblique rugulae which reach the end of vertexal lobes; frontal carina and antennal scrobe absent; clypeus with a conspicuous median longitudinal carina; hypostoma with an inconspicuous or low and broad median and low submedian processes in addition to small to conspicuous lateral processes; the median process somewhat emaginate or with a concavity in the center; antenna with a 3-segmented club; maximal diameter of eye (much) longer than antennal segment X; median ocellus often present. Promesonotal dome with a small to inconspicuous prominence or mound on its posterior slope; humerus not produced; the dome much narrower at the humeri than at the bottom. Petiole (a little) longer than postpetiole (excluding helcium); postpetiole not massive. First gastral tergite rugoso-punctate weakly but densely.

Minor — Dorsum of head largely smooth; area between antennal insertion and eye with rugulae; dorso-lateral and posterodorsal faces of head sometimes shagreened; preoccipital carina conspicuous dorsally and laterally; median part of clypeus smooth; median longitudinal carina of clypeus absent, or sometimes present but inconspicuous or weak; antenna with a 3-segmented club; scape extending far beyond posterolateral margin of head; maximal diameter of eye almost as long as, or a little shorter or a little longer than antennal segment X. Promesonotal dome smooth and shining, usually bearing very long hairs dorsally, in lateral view with a low or inconspicuous mound on its posterior slope; humerus of the dome in dorsal-oblique view not raised/produced; mesopleuron, metapleuron and lateral face of propodeum smooth and shining, or at most very weakly punctured partly; propodeal spine in lateral view spiniform or elogate-triangular, directing upward. Petiole almost as long as postpetiole (excluding helcium); postpetiole relatively large.

Type Material
Eguchi (2008) - Syntypes: 3 minors, “Cochinchine (Dugas)” [S. Vietnam],, examined, one of them designated here as the lectotype.

References based on Global Ant Biodiversity Informatics

 * Chapman, J. W., and Capco, S. R. 1951. Check list of the ants (Hymenoptera: Formicidae) of Asia. Monogr. Inst. Sci. Technol. Manila 1: 1-327
 * Eguchi K. 2008. A revision of Northern Vietnamese species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae). Zootaxa 1902: 1-118.
 * Eguchi K.; Bui T. V.; Yamane S. 2011. Generic synopsis of the Formicidae of Vietnam (Insecta: Hymenoptera), part I  Myrmicinae and Pseudomyrmecinae. Zootaxa 2878: 1-61.
 * Forel A. 1911. Fourmis nouvelles ou intéressantes. Bull. Soc. Vaudoise Sci. Nat. 47: 331-400.
 * Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
 * Huong N. T. T., P. V. Sang, and B. T. Viet. 2015. A preliminary study on diversity of ants (Hymenoptera: Formicidae) at Hon Ba Nature Reserve. Environmental Scientific Conference 7: 614-620.
 * Jaitrong W., B. Guenard, E. P. Economo, N. Buddhakala, and S. Yamane. 2016. A checklist of known ant species of Laos (Hymenoptera: Formicidae). Asian Myrmecology 8: 1-32. DOI: 10.20362/am.008019
 * Jaitrong W.; Nabhitabhata, J. 2005. A list of known ant species of Thailand. The Thailand Natural History Museum Journal 1(1): 9-54.
 * Ngoc Anh L., K. Ogata, and S. Hosoishi. 2010. Ants of agricultural fields in Vietnam (Hymenoptera: Formicidae). Bull. Inst. Trop. Agr. Kyushu Univ. 33: 1-11.
 * Ogata K. 2005. Asian ant inventory and international networks. Report on Insect inventory Project in Tropic Asia TAIIV: 145-170.
 * Yamane S.; Bui T. V.; Ogata K.; Okido H.; Eguchi K. 2002. Ant fauna of Cuc Phuong National Park, North Vietnam (Hymenoptera: Formicidae). Bulletin of the Institute of Tropical Agriculture Kyushu University 25: 51-62.
 * Zryanin V. A. 2011. An eco-faunistic review of ants (Hymenoptera: Formicidae). In: Structure and functions of soil communities of a monsoon tropical forest (Cat Tien National Park, southern Vietnam) / A.V. Tiunov (Editor). – M.: KMK Scientific Press. 2011. 277 р.101-124.