Pheidole fortis, Eguchi, Katsuyuki, 2006

Eguchi, Katsuyuki, 2006, Six new species of Pheidole Westwood from North Vietnam (Hymenoptera, Formicidae), Revue Suisse de Zoologie 113 (1), pp. 115-131 : 115

Pheidole fortis sp. n.

Figs 2A-I

Pheidole sp. eg-160 : Bui & Eguchi, 2003 (a list of local ant fauna).

HOLOTYPE. - Major from colony Eg02-VN-264. Type locality: Cat Cat (a trail to Mt. Phansipan, ca. 1300-1400 m alt.), Sa Pa, Lao Cai, Vietnam [K. Eguchi leg., 3/v/2002]. Depository: IEBR. PARATYPES. - 1 major and 19 minors from the same colony to which the holotype belongs. Depository: IEBR, MHNG, MCZC, BMNH, NHMW, FSKU, ACEG.

NON-TYPE MATERIAL EXAMINED. - Vietnam: Vinh Phuc: Tam Dao N. P., ca. 950 m alt. [SKY, 2001]. Thailand: Chiang Mai: Doi Pui, ca. 1200 m alt., Doi Suthep-Pui N. P. [Eg01-TH- 113]. Eguchi’s informal species code “ Pheidole sp. eg-160 ” has been applied to these specimens. DIAGNOSIS. - Head densely covered with short decumbent to subdecumbent hairs entirely (major); frons with longitudinal rugulae which run toward posterolateral corner of vertexal lobes (major); promesonotal dome lacking a conspicuous prominence on its posterior declivity (minor); postpetiole massive (major and minor).

DESCRIPTION. - Major: TL 4.4-4.8 mm, HL 2.12-2.23 mm, HW 1.79-2.05, SL

0.90-0.91 mm, FL 1.33-1.39 mm, CI 84-92, SI 44-51, FI 67-78 (N=4); body reddishbrown with paler alitrunk and appendages; head in full-face view very weakly convex laterad, broadly and deeply concave posteromedially, in profile not impressed on vertex, densely covered with short decumbent to subdecumbent hairs entirely; frons with longitudinal rugulae which run toward posterolateral corner of vertexal lobes; frontal carina and antennal scrobe absent; median part of clypeus with a median longitudinal carina; hypostoma with a pair of low processes and an inconspicuous process (a total of three median processes) in addition to the process just mesal to each mandibular base (lateral processes); lateral processes conspicuous, but smaller than lateral ones of the three median processes; antenna with a 3-segmented club; scape just reaching or a little exceeding midlength of head when it laid backward; EL ≥ LASX; LG 1.8-2.2 times as much as EL; promesonotal dome sparsely rugose transversely, with interspaces smooth and shining, with a much reduced prominence on its posterior declivity; lower part of mesopleuron smooth and shining often with several rugulae; lateral face of propodeum with rugulae; propodeal spine short, narrowly based; petiole as long as postpetiole (excluding helcium); petiolar node in anterior view shallowly and broadly concave dorsally; postpetiole massive, 2.2-2.5 times as broad as petiolar node, with an angle laterally; at least anterior 1/3 of first gastral tergite rugoso-punctured.

Minor: TL 2.3-2.8 mm, HL 0.71-0.75 mm, HW 0.64-0.71 mm, SL 0.79-0.87 mm, ML 1.01-1.07 mm, FL 0.92-0.97 mm, CI 90-95, SI 118-124, FI 134-144 (N=5); body yellowish-brown with paler appendages; head in full-face view oval, smooth and shining over the surface; median part of clypeus almost smooth and shining, often with a median longitudinal carina; preoccipital carina complete but weak dorsally; antenna with a 3-segmented club; scape extending far beyond posterolateral margin of head; EL<LASX; promesonotal dome smooth and shining, in profile without a conspicuous prominence on its posterior declivity, with an inconspicuous mound dorsolaterally; lower part of mesopleuron smooth and shining largely; lateral face of propodeum very weakly punctured; propodeal spine small, elongate-triangular, narrowly based; petiole shorter than postpetiole (excluding helcium); postpetiole massive, 2.1-2.5 times as broad as petiolar node.

REMARKS. - This species is similar to Pheidole wroughtoni Forel (the type material housed in MHNG was examined), but well distinguished from the latter by the following characteristics: in the major of the latter vertex and dorsum of vertexal lobe in profile forming an obtuse angle; in the minor of the latter EL>LASX; the minor of the latter having a conspicuous prominence on the posterior declivity of promesonotal dome. The minor of this species is similar to that of Pheidole magna sp. n. (see below), but the latter has a conspicuous prominence on the posterior declivity of promesonotal dome.

DISTRIBUTION. - N. Vietnam and N. Thailand.

BIONOMICS. - This species inhabits open forests and forest edges in hilly areas (900-1400 m alt. in N. Vietnam). It nests in the soil.