Pheidole plagiaria F. Smith

Eguchi, K., 2008, A revision of Northern Vietnamese species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae)., Zootaxa 1902, pp. 1-118 : 73-77

Pheidole plagiaria F. Smith

Figs. 20a-g, 32e, 32f

Pheidole plagiaria F. Smith , 1860: 112. Eguchi, Bui et al. 2005: 90 (checklist). Syntypes: 3 majors & 3 minors, "Bac" [Batjan, Indonesia], OXUM TYPE HYM: 983 1-2/6, 3-4/6 & 5-6/6, examined.

Pheidole divergens Mayr , 1867: 97. Mayr, 1879: 675 (junior synonym of P. plagiaria ). Syntypes: major, minor, queen & male, Indonesia, not examined.

Pheidole peguensis r. yomensis Forel , 1903: 253. Syn.n. Syntype: 1 major, "Lower Burma Pegu Yoma 1 1900 Bingham" [Myanmer], MHNG, examined, designated as lectotype [Fig. 32e, 32f].

Current subspecies (Bolton, 1995): nominal plus moica Forel , 1911c: 222, syntype(s): major, Central part of Southern Vietnam, not examined; palawanica Stitz , 1925: 118, syntypes: 2 majors, "N. Palawan Binaluan Boettcher" [Philippines], ZMHB, examined; rectilineata Viehmeyer , 1916b: 288-289, syntype(s): major, Sulawesi (in copal), not examined.

Other material examined: S. China: Hainan: Jianling N.R., Wanling [J. Fellowes]. Vietnam: Thai Nguyen: My Yen Commune Forest, 21°35'N, 135°36'E, Na Hau Village [Eg01-VN-147]; Vinh Phuc: Tam Dao N.P., 21°27'N, 105°38'E, 800-900 m alt. [Eg99-VN-037, -038], Tam Dao N.P., 900 m alt. [Eg99-VN- 001, -005, -008, -009; Eg01-VN-104, -106], Tam Dao N.P., 900-1100 m alt. [Eg99-VN-052], Tam Dao N.P., 1100 m alt. [VN98-SKY-14]; Ha Tay (mislabeled as "Ha Tai"): Ba Vi N.P., 400-800 m alt. [Eg99-VN-119]. Thailand: Chiang Mai: Doi Ang Khang HQ, 1300 m alt. [TH98-SKY-28], Doi Chiang Dao [Eg01-TH-122, - 134, -148], Doi Chiang Dao, 500-600 m alt. [TH98-SKY-18], Doi Suthep-Pui N.P., 600 m alt. [TH98-SKY- 04], Doi Suthep-Pui N.P., 800 m alt. [TH98-SKY-08], Doi Suthep-Pui N.P., 800-900 m alt. [Eg01-TH-069, - 096, -098, -100], Doi Suthep-Pui N.P., 900 m alt. [Eg01-TH-082, -083, -086, -087, -089, -090], Doi Suthep-Pui N.P., 1200 m alt. (Doi Pui) [Eg01-TH-110, -118]; Nakhonratchasima: Khao Yai N.P. [TH00-SKY-24], nr. Sakaerat Environmental Research Centre [Eg99-TH-020; Eg01-TH-532, -549]; Chanthabri: Khao Soi Dao [Eg01-TH-021]; Chacheongsao: Lumchangwat Station, Khao Ang Reu Nai W.S. [TH03-SKY-69]; Pattani: Soi Khao [TH98-SKY-40]; Trang: Khao Chong Waterfall [Eg01-TH-708, -714, -723, -736, -745, -746, -758]; Songkhla: Ton Nga Chang, nr. Hat Yai [Eg01-TH-613, -615, -626, -628], Songkhla Univ. (Khao Kor Hong) [Eg01-TH-597, -598]; Narathiwat: Bala area of Bala-Hala W.S. [Eg01-TH-636]. Myanmar: Chin: between Kampetlet and Natmataung N.P., 1670 m alt. [MM02-SKY-46], between Kampetlet and Natmataung N.P., 1700 m alt. [MM02-SKY-02], between Kampetlet and Natmataung N.P., 1760 m alt. [MM02-SKY-34], Natmataung N.P., 2000 m alt. [MM02-SKY-10], Natmataung N.P., 21°13'N, 93°56'E, 2000 m alt. [MM02-SKY- 24, -26, -29]. W. Malaysia: Selangor: Ulu Gombak [FI92MG-174, -383]. E. Malaysia: Sabah: Deramakot Forest Reserve [C. Bruhl], Gunong Rara [Eg96-BOR-351, -363; Eg97-BOR-526, -534, -556, -566], Poring, 450- 500 m alt. [Eg96-BOR-271], Poring, 500-550 m alt. [Eg96-BOR-294], Poring, 600 m alt., [T. Kikuta's colony: 8-A, 43A, 731, 6XI2306S1-4], Sepilok Forest [Eg97-BOR-412, -418, -460, -464; Eg98-BOR-871], Tawau Hills Park [Sk. Yamane]; Sarawak: Lambir Hills N.P. [Eg98-BOR-803, -808, -817, -819, -825, -829], Lambir Hills N.P. (Inoue Trail) [SR04-SKY-67]. Brunei: Belalong Forest Section [Eg99-BOR-211], Merimbun Heritage Park (=Tasek Merimbun) [Eg99-BOR-007, -008, -028, -030, -035, -070, -074, -123, -150, -552, -567, -568; Eg00-BOR-019, -022, -064]. Indonesia: E. Kalimantan: Sangkimah, Kutai N.P. [Sk. Yamane]; W. Sumatra: Sukarami, nr. Padang [FI92-66, -83; FI96-162; M. Kawamura's colony: 9/29c (1999)]; Krakatau Is.: P. Rakata Besar [Kagoshima Univ. Krakatau Exp.]; W. Java: Cibodas [M. Kawamura's colony: D28 (1997)], Kebun Raya, Bogor [FI95-534, -784; Sk. Yamane; M. Kawamura's colony: 154 (1998), 9/26a (1999), 10/5b (1999), 10/5c (1999)], G. Halimun [FI98-373; M. Kawamura's colony: 5/6a (1998)], Pangandaran [FI95-705], Ciater, 1350 m alt. [Syaukani]; C. Java: Borobudur, nr. Yogyakarta [Sk. Yamane], Kaliadem, 800-1000 m alt., G. Merapi [JV02/03-SKY-38]; E. Java: Sumberbrantas, 1600 m alt., Tulungrejo, Batu [JV02/03-SKY-78, -79]; Bali: Kebun Raya [FI94-137]. Philippines: Leyte: Baybay, Mt. Pangasugan, Calbiga-a River [Zettel].

Worker measurement & indices: Major (n=5). - HL 1.65-1.89 mm, HW 1.59-1.77 mm, CI 91-98, SL 1.03-1.22 mm, SI 59-71, FL 1.42-1.70 mm, FI 85-99.

Minor (n=5). - HL 0.79-0.93 mm, HW 0.67-0.75 mm, CI 81-85, SL 1.01-1.20 mm, SI 146-163, FL 1.12-1.36 mm, FI 162-181.

Worker description

Major. - Head in lateral view not or only very weakly impressed on vertex; posterior margin of head in full-face view relatively widely and deeply concave; longitudinal rugulae running on the frons and then spreading posterolaterad as they run almost transversely on the posteriormost part of the dorsum of vertexal lobe; posterolateral face of head with oblique rugulae which run anteroventrad from dorsal face of vertexal lobe; frontal carina conspicuous; antennal scrobe inconspicuous or only weakly impressed; median longitudinal carina of clypeus present but weak, or rarely absent; median and submedian processes of hypostoma inconspicuous or absent; lateral processes conspicuous; outer surface of mandible covered with relatively long decumbent hairs; antenna with a 3-segmented club; maximal diameter of eye a little longer, as long as, or a little shorter than antennal segment X. Promesonotal dome in dorsal view transversely rugose with interspaces smooth to shagreened, or smooth to shagreened with sparse several transverse rugulae; the dome in lateral view with a low prominence or mound on its posterior slope; humerus of the dome not or hardly produced laterad; the dome at the humeri narrower than at the bottom; mesopleuron, metapleuron and lateral face of propodeum rugoso-reticulate, with enclosures punctured. Outer surface of foretibia bearing relatively long decumbent-suberect hairs. Petiole longer than postpetiole (excluding helcium); postpetiole not massive. First gastral tergite largely smooth and shining, but sometimes weakly punctured around its articulation with postpetiole.

Minor. - Frons and dorsal face of vertex smooth and shining, or very weakly punctured or rugoso-punctate; area between antennal insertion and eye rugose or rugoso-punctate; preoccipital carina well-developed; median part of clypeus with a zigzag or ramified (but rarely straight) median carina which is usually accompanied with weak rugulae; 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 and shining, or in dorsal view concentrically rugose, with a median area smooth and shining or very weakly punctured; the posterior slope of the dome with a low mound which bears several (>2) standing hairs; humerus in dorso-oblique view not or hardly produced; mesopleuron, metapleuron and lateral face of propodeum punctured, usually overlain by weak rugoso-reticulation; propodeal spine horn-like or elongate-triangular, narrowly based, directing relatively upward. Petiole longer than postpetiole (excluding helcium); postpetiole not massive.

Recognition: The syntype major of Pheidole peguensis r. yomensis Forel agrees with the majors of Thai populations of Pheidole plagiaria (e.g., Eg01-TH-083). Thus, I here synonymize Pheidole peguensis r. yomensis with P. plagiaria . Three Pheidole minors which are pinned together and labeled as "Ph plagiaria Sm v. moica For .... Mois Cochinchine (Dugas)" were examined ( MHNG). The top of the pin is undoubtedly a minor of Pheidole plagiaria , while the middle is the other Pheidole species, and the bottom is Pheidologeton sp. Forel (1911) described " P. plagiaria var. moica " based on the major subcaste, and so I refrain from resolving the synonymy.

This species is characterized among Indo-Chinese species by the combination of the following features: in the major posterior margin of head in full-face view relatively widely and deeply concave; in the major the posteriormost part of the dorsum of vertexal lobe almost transversely rugose; in the major and minor the posterior slope of promosonotal dome with a prominence or mound; in the major outer surface of foretibia bearing relatively long decumbent-suberect hairs; in the minor median part of clypeus with a zigzag or ramified (but rarely straight) median carina which is usually accompanied with weak rugulae. The minor of this species is similar to that of P. binghami , but in the latter median part of clypeus has no rugula and the mound on the posterior slope of promesonotal dome has only a pair of hairs.

Distribution & bionomics: Widely distributed in the Indo-Chinese, Indo-Malayan subregions and Austro-Malayan subregion. Indo-Malayan populations inhabit well-developed forests, and usually nest in rotting logs and wood fragments. On the other hand, Indo-Chinese populations often occur in forest edges and even in open lands adjacent to forests, and usually nest in the soil (Eguchi 2001).