Pheidole pieli

Eguchi (2008) - Indo-Chinese populations usually occur in forest edges and patches with poorly developed vegetation than in well-developed forests, and nest in the soil. On the other hand, Japanese populations usually occur in relatively developed forests, and nest in wood fragments on the ground as well as in the soil (Eguchi et al. 2004, Eguchi, Yamane & Zhou 2005). According to Eguchi (2004b) workers gather and feed on seeds of sesame and amaranthus put on the ground in S. Japan. Majors serve as repletes (Handa 1992).

Identification
Eguchi (2008) - This species is characterized among Indo-Chinese species by the combination of the following features: in the major frontal carina inconspicuous, present just as rugula(e); in the major hypostoma in the middle with 3 processes (median process rarely inconspicuous or absent); in the minor preoccipital carina absent or evanescent dorsally; in the minor promesonotal dome smooth and shining, often with weak transverse rugula(e); in the major and minor posterior slope of promesonotal dome without a conspicuous prominence/mound; in the minor propodeal spine usually reduced to a tiny dent.

P. pieli is most similar to Pheidole laevicolor and Pheidole taipoana among Indo-Chinese species, but the minor of the latter two has rather developed propodeal spines and rather gentle posterior slope of promesonotal dome. Head in lateral view is more strongly concave on vertex in the major of P. taipoana than in that of P. pieli.

Key to Pheidole of North Vietnam

Distribution
Known from N. Vietnam, S. Japan, China and Thailand.

Distribution based on Regional Taxon Lists
Oriental Region: Thailand, Vietnam. Palaearctic Region: China, Democratic Peoples Republic of Korea, Japan, Republic of Korea.

Nomenclature

 *  pieli. Pheidole pieli Santschi, 1925f: 83 (s.w.) CHINA. Ogata, 1982: 195 (m.). Senior synonym of incensa: Eguchi, Yamane & Zhou, 2007: 265. See also: Wu & Wang, 1995: 100.
 * incensa. Pheidole rinae subsp. incensa Wheeler, W.M. 1928c: 13 (s.w.) CHINA. Junior synonym of pieli: Eguchi, Yamane & Zhou, 2007: 265.

Worker
Eguchi (2008) - Major (data from Eguchi, Yamane & Zhou 2007). — HL 0.79–1.03 mm; HW 0.69–0.97 mm; CI 85–96; SL 0.35–0.48 mm; SI 46–51; FL 0.44–0.60 mm; FI 59–66. Minor (data from Eguchi, Yamane & Zhou 2007). — HL 0.38–0.47 mm; HW 0.33–0.43 mm; CI 85–92; SL 0.31–0.42 mm; SI 89–108; FL 0.32–0.44 mm; FI 92–111.

Major — Head in lateral view hardly or weakly (rarely strongly) impressed on vertex; frons longitudinally rugose; vertex and dorsal and dorsolateral faces of vertexal lobe reticulate, rugoso-reticulate or obliquely rugose, or rarely sculptured dimly; frontal carina inconspicuous, present just as rugula(e); antennal scrobe absent or inconspicuous; median longitudinal carina on clypeus absent or evanescent, or sometimes present but very weak; median process of hypostoma usually conspicuous, but rarely inconspicuous or almost absent; submedian and lateral processes always conspicuous; antenna with a 3-segmented club; maximal diameter of eye (a little) longer than antennal segment X. Promesonotal dome smooth and shining, sparsely sculptured with transverse or irregular rugulae, in lateral view at most with an inconspicuous mound on its posterior slope; humerus of the dome weakly or sometimes very weakly produced laterad; the dome at the humeri almost as broad as or a little broader than at the bottom (rarely a little narrower than at the bottom). Petiole (much) longer than postpetiole (excluding helcium); postpetiole not massive. First gastral tergite usually smooth, excluding weakly rugoso-punctate area around its articulation with postpetiole, but rarely shagreened entirely.

Minor — Frons largely smooth and shining, or rarely shagreened with weak rugulae; vertex and dorsolateral face of head almost smooth, or very weakly rugoso-reticulate or rugoso-punctate; preoccipital carina absent or evanescent dorsally; median part of clypeus smooth and shining; the median longitudinal carina absent, or rarely present but very weak; antenna with a 3-segmented club; scape not reaching or exceeding the posterior margin of head by at most the length of second antennal segment; maximal diameter of eye (a little) longer than antennal segment X (rarely as long as antennal segment X). Promesonotal dome smooth and shining, often with weak transverse rugula(e) on its anterior slope, in lateral view without a mound on its relatively steep posterior slope; humerus of the dome in dorso-oblique view not or hardly produced; mesopleuron, metapleuron and lateral face of propodeum usually almost smooth, but sometimes weakly punctured; propodeal spine usually reduced to a tiny dent. Petiole much longer than postpetiole (excluding helcium); postpetiole not massive.

Type Material
Eguchi (2008):

Syntypes: 2 majors & 9 minors, “Zo-Se 27-7-24” [Zo-Ce, China],, examined.

Pheidole rinae subsp. incensa. Syntypes: 3 majors & 3 minors, “Peta, Foochow, Silvestri” [Foochow, China], cotype- 20669, examined.