Pheidole elongicephala

This species occurs in woody habitats, and nests in rotting wood material (logs, stubs) and in the soil.

Identification
Pheidole elongicephala, Pheidole binghamii and Pheidole ochracea are morphologically very similar (and probably closely related). Differences between P. elongicephala and P. binghamii are as follows: head behind eyes in full-face view more elongated and tapered posterad in the minor of the former than in that of the latter; mound on the posterior slope of promesonotal dome bearing usually 4 standing hairs in the minor of the former, but usually only a pair of standing hairs in the minor of the latter. The body size of both the subcastes is almost constantly larger in P. elongicephala than in P. binghamii. The two species are allopatric or parapatric (range of P. binghamii: Myanmar, Thailand, S. Vietnam). Differences between P. elongicephala and P. ochracea are as follows: head behind eyes in full-face view more elongated and tapered posterad in the minor of the former than in that of the latter; occipital carina of the minor much more developed in the former than in the latter; the long axis of eye having 8–9 ommatidia in the minor of the former, but 6–7 ommatidia in that of the latter. They are sympatric in S. China and N. Vietnam.

Distribution
Known from N. Vietnam and S. China.

This taxon was described from Vietnam.

Nomenclature

 *  elongicephala. Pheidole elongicephala Eguchi, 2008: 20, figs. 4a-h, (s.w.m.) VIETNAM.

Worker
Holotype (major). — HL 1.76 mm; HW 1.56 mm; CI 89; SL 1.18 mm; SI 76; FL 1.56 mm; FI 100. Nontype major (n=4). — HL1.68–1.78 mm; HW 1.51–1.57 mm; CI 88–90; SL 1.13–1.16 mm; SI 74–75; FL 1.53–1.56 mm; FI 99–102. Minor (n=5, including one paratype minor). — HL 0.78–0.85 mm; HW 0.58–0.64 mm; CI 75–76; SL 1.06–1.19 mm; SI 176–187; FL 1.11–1.25 mm; FI 187–197.

Major. — Body deep yellowish-brown, brown or deep reddish-brown, with paler appendages. Head in lateral view not or weakly impressed on vertex; vertexal lobes in full-face view relatively close to each other; frons and anterior part of vertex longitudinally rugose; posterior part of vertex and dorsum of vertexal lobe rugoso-reticulate or reticulate; clypeus without a conspicuous median longitudinal carina; frontal carina conspicuous; antennal scrobe very shallow; hypostoma with a very low or inconspicuous median process and a pair of low or inconspicuous submedian processes in addition to a pair of conspicuous lateral processes; antenna with a 3-segmented club; maximal diameter of eye shorter than antennal segment X. Promesonotal dome sparsely rugose transversely, with interspaces smooth and shining; a conspicuous prominence present on its posterior slope; humerus not or hardly produced laterad; the dome at the humeri much narrower than at the bottom; mesopleuron and metapleuron weakly punctured, overlain by rugoso-reticulation; propodeal spine narrowly based. Petiole longer than postpetiole (excluding helcium); postpetiole not massive. First gastral tergite smooth entirely, or shagreened only around its articulation with postpetiole.

Minor. — Body yellowish-brown or brown, with paler appendages. Head in full-face view elongate-elliptical, tapered posterad behind eyes; frons and vertex smooth or shagreened; median portion of clypeus smooth; median longitudinal carina very weak or absent; occipital carina forming a well-developed collar; antenna with a 3-segmented club; scape extending far beyond posterolateral margin of head; maximal diameter of eye much shorter than antennal segment X; 8–9 ommatidia present on the long axis of eye; promesonotal dome smooth and shining, in lateral view with a low mound on its gentle posterior slope; the mound bearing usually 4 standing hairs; humerus in dorso-oblique view not raised/produced; mesopleuron, metapleuron and lateral face of propodeum punctured, often overlain by weak rugulae; propodeal spine elongate-triangular, directing upward; petiole (a little) longer than postpetiole (excluding helcium); postpetiole not massive.

Type Material
Holotype, major, Cuc Phuong N.P. (“Dong Nguoi Xua” Area), Ninh Binh, N. Vietnam [Eg09vi05-08 (K. Eguchi leg., 09/JUN/2005)] (IEBR); paratypes: 7 majors, 9 minors & 2 males, same data as holotype (IEBR, MHNG, MCZC, & ACKE).