Pheidole fortis

This species inhabits open forests and forest edges, and nests in the soil (Eguchi 2006).

Identification
Eguchi (2008) - This species is characterized among Indo-Chinese species by the following characteristics: in the major head densely covered with short decumbent to subdecumbent hairs entirely; in the major frons with longitudinal-oblique rugulae which reach posterolateral corner of vertexal lobes; in the minor promesonotal dome lacking a conspicuous prominence on its posterior slope; in the major and minor postpetiole massive. Pheidole fortis is similar to Pheidole wroughtonii Forel (the type material housed in MHNG was examined), but well distinguished from the latter in which vertex and dorsum of vertexal lobe in lateral view forms an obtuse angle in the major, maximal diameter of eye longer than antennal segment X in the minor, and the posterior slope of promesonotal dome has a conspicuous prominence/mound in the minor. The minor of this species is similar to that of Pheidole magna, but the minor of P. magna has a conspicuous prominence/mound on the posterior slope of promesonotal dome (see also Eguchi 2006).

Key to Pheidole of North Vietnam

Distribution
Known from N. Vietnam and Thailand.

Distribution based on Regional Taxon Lists
Oriental Region: Vietnam.

Nomenclature

 *  fortis. Pheidole fortis Eguchi, 2006: 118, figs. (s.w.) VIETNAM. See also: Eguchi, 2008: 31.

Worker
Eguchi (2008) - Major (data from the original description). — HL 2.12–2.23 mm, HW 1.79–2.05 mm, CI 84–92, SL 0.90–0.91 mm, SI 44–51, FL 1.33–1.39 mm, FI 67–78. Minor (data from the original description). — HL 0.71–0.75 mm, HW 0.64–0.71 mm, CI 90–95, SL 0.79– 0.87 mm, SI 118–124, FL 0.92–0.97 mm, FI 134–144.

Major — Head in lateral view not or hardly impressed on vertex; head densely covered with short decumbent to subdecumbent hairs entirely; frons with longitudinal rugulae which reach posterolateral corner of vertexal lobes; frontal carina and antennal scrobe absent; clypeus with a median longitudinal carina; hypostoma with an inconspicuous median process and low or relatively developed submedian processes in addition to small lateral processes; antenna with a 3-segmented club; maximal diameter of eye almost as long as or longer than antennal segment X. Promesonotal dome with a much reduced prominence on its posterior slope; humerus not or very weakly produced laterad; the dome at the humeri as broad as or narrower than at the bottom. Petiole as long as postpetiole (excluding helcium); postpetiole massive. First gastral tergite rugoso-punctured at least in its anterior 1/3.

Minor — Dorsum of head largely smooth and shining; preoccipital carina complete but weak dorsally; median part of clypeus almost smooth, usually with a conspicuous to weak median longitudinal carina; antenna with a 3-segmented club; scape extending far beyond posterolateral margin of head; maximal diameter of eye shorter than antennal segment X. Promesonotal dome smooth, in lateral view lacking a conspicuous prominence/mound on its posterior slope; humerus of the dome in dorso-oblique view hardly to weakly produced laterad; propodeal spine small, elongate-triangular. Petiole shorter than postpetiole (excluding helcium); postpetiole massive.

Type Material
Eguchi (2008) - Holotype: major, “Cat Cat (a trail to Mt. Phansipan), ca. 1300–1400 m alt., Sa Pa, Lao Cai, Vietnam, Eg02-VN-264”,, examined; paratypes: 1 major & 19 minors, same data as holotype, IEBR, , , , & , examined.