Pheidole dugasi Forel, 1911

Eguchi, Katsuyuki, 2008, A revision of Northern Vietnamese species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae), Zootaxa 1902 (1), pp. 1-118 : 17-21

Pheidole dugasi Forel

Figs. 3a–g , 32a, b

Pheidole dugasi Forel, 1911c: 222–223 . Yamane et al. 2003 (checklist), Eguchi, Bui et al. 2005: 89 (checklist). Syntypes: 3 minors, “Cochinchine (Dugas)” [S. Vietnam], MHNG, examined, one of them designated here as the lectotype [ Fig. 32a, 32b ].

Pheidole sp. eg-59 (? ocellata Zhou). Eguchi 2003: 337 (description of male genitalia).

Other material examined: S. China: Guangxi: Shiwandashan N.R., Quinzhou [J. Fellowes]; Hainan: Wuzhishan N.R., Qiongzhong , 700 m alt. [J. Fellowes], Wangxia N.R., nr. Bawangling, Changjiang [J. Fellowes], Jianling N.R., Wanling [J. Fellowes]. N . Vietnam: Ha Tay (mislabeled as Ha Tai ): Ba Vi N.P., 21°03’N, 105°22’E, ca. 400 m alt. [K. Eguchi]; Ninh Binh: Cuc Phuong N.P., 20°14’N, 105°36’E [VN98- SKY-23; Eg 01-VN-200, -201; Eg 10vi05-01]. S . Vietnam: Dong Nai: S. Cat Tien N.P., <160 m alt. [Eg 04- VN-508, -539] . Thailand: Chiang Mai: Campus of Chiang Mai Univ. [Eg01-TH-162], Doi Chiang Dao [Eg01- TH-142], Doi Chiang Dao , 500–600 m alt. [Sk. Yamane]; Chanthaburi: Khao Soi Dao W.S. [TH01-SKY-03; Eg 01-TH-002, -020, -034; H. Okido]; Chacheongsao: Khao Ang Reu Nai W.S., near the Headquarters [TH03- SKY-89] .

Worker measurements & indices: 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; SL 1.15–1.36 mm; SI 124–137; FL 1.47–1.67 mm; FI 159–175.

Worker description

Major. — Head in lateral view roundly convex dorsally, not impressed on vertex; frons with longitudinaloblique 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; dorsolateral 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.

Recognition: 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 (Wheeler) and P. smythiesii Forel. 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 & bionomics: Known from Vietnam, S. China and Thailand. This species usually nests under the ground in woody gardens and forest edges. Majors serve as repletes (e.g., Eg01-TH-034, -142). In S. Cat Tien N.P. (S. Vietnam) I observed masses of workers retrieving seeds from mammal feces.

Pheidole elongicephala Eguchi sp.n.

Figs. 4a–h

Pheidole sp. B ( aff. aglae Forel ). Yamane et. al. 2003: 58 (checklist).

Pheidole aglae Forel. Misidentification made by Eguchi et al. 2004 (ecological study).

Type material examined: 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).

Other material examined: S. China: Hong Kong: Taipo Kau N.P., New Territory [Eg00-HK-028]. Vietnam: Thai Nguyen: My Yen Commune Forest, 21°35’N, 105°36’E, Na Hau Village [Eg01-VN-158]; Bac Giang: W. Yen Tu N.P. (=Tay Yen Tu N.P.), 21°10–11’N, 106°43–44’E, 190–370 m alt. [Eg03-VN-030, -040, -135, -153, -160; B&E03-12]; Ha Tay (mislabeled as Ha Tai): Ba Vi N.P., 21°03’N, 105°22’E, 400–700 m alt. [Eg02-VN-009, -022]; Ninh Binh: Cuc Phuong N.P. [Eg11iv05-14; Eg15vi05-07]. Part of specimens to which Eguchi’s informal species code “ Pheidole sp. eg-101” has been applied (Eguchi, Bui et al. 2005: 90) is P. elongicephala , and the remainder is P. ochracea .

Worker measurements & indices: 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). — HL 1.68–1.78 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.

Worker description

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.

Recognition: Pheidole elongicephala , P. binghamii and P. ochracea sp.n. are morphologically very similar to each other (and probably very closely related to each other). 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 sp.n. 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 & bionomics: Known from N. Vietnam and S. China. This species occurs in woody habitats, and nests in rotting wood material (logs, stubs) and in the soil.

Figures

FIGURE 3a–d, Pheidole dugasi, nontype major [Eg01-VN-200] — a, head in full-face view; b, head in lateral view; c, mesosoma and waist in dorsal view; d, mesosoma and waist in lateral view.

FIGURE 4a–d, Pheidole elongicephala sp.n., major [Eg09vi05-08] — a, holotype, head in full-face view; b, paratype, head in lateral view; c, paratype, mesosoma and waist in dorsal view; d, paratype, mesosoma and waist in lateral view.

FIGURE 32, Lectotypes (a, c, e, g) designated in the present paper and their labels (b, d, f, h) — a, b, Pheidole dugasi Forel (arrows indicating the lectotype); c, d, “Pheidole rhombinoda stella Forel”(arrow indicating the lectotype); e, f, “Pheidole peguensis yomensis Forel”; g, h, “Pheidole sulcaticeps yeensis Forel”.