Pheidole laevithorax, Eguchi, 2008

Eguchi, Katsuyuki, 2008, A revision of Northern Vietnamese species of the ant genus Pheidole (Insecta: Hymenoptera: Formicidae: Myrmicinae), Zootaxa 1902 (1), pp. 1-118 : 49-52

Pheidole laevithorax sp.n.

Figs. 13a–g

Pheidole sp. eg-174 ( cf. protea Forel ). Eguchi, Bui et al. 2005: 91 (checklist).

Type material examined: Holotype: major, Ba Vi N.P., 21°03’N, 105°22’E, 670 m alt., Ha Tay (misspelled as Ha Tai on the label), N. Vietnam [K. Eguchi leg., colony: Eg01-VN-230] ( IEBR); paratypes: 11 majors & 12 minors from the same colony as holotype ( IEBR, MCZC, MHNG & ACEG).

Other material examined: N. Vietnam: Bac Giang: W. Yen Tu N.P. (= Tay Yen Tu N.P.), 21°10’N, 106°43’E, 1070 m alt. [Eg03-VN-122] ; Quang Ninh: Chua Yen Tu , 21°09’N, 106°43’E, 720–845 m alt. [Eg04-VN-069]; Ha Tay (misspelled as Ha Tai): Ba Vi N.P., 21°03’N, 105°22’E, 800 m alt. [Eg02-VN-050, - 053, -055, -067, -069, -076]. Eguchi’s informal species code “ Pheidole sp. eg-174” applies to this species .

Worker measurements & indices: Holotype (major). — HL 1.34 mm; HW 1.28 mm; CI 96; SL 0.76 mm; SI 59; FL 1.00 mm; FI 78.

Nontype major (n=4). — HL 1.25–1.33 mm; HW 1.21–1.23 mm; CI 92–98; SL 0.75–0.79 mm; SI 62–65; FL 0.97–1.02 mm; FI 79–83.

Minor (n=4, including one paratype minor). — HL 0.63–0.70 mm; HW 0.53–0.58 mm; CI 84; SL 0.76– 0.84 mm; SI 141–145; FL 0.82–0.90 mm; FI 154–156.

Worker description

Major. — Head in lateral view not or hardly impressed on vertex; frons rugose longitudinally; vertex rugoso-reticulate longitudinally or reticulate; dorsal and dorsolateral faces of vertexal lobe reticulate; frontal carina conspicuous; antennal scrobe inconspicuous to weak; clypeus without a median longitudinal carina; median process of hypostoma low or inconspicuous; submedian processes low or moderately developed; lateral processes developed well, located rather ventrally; antenna with a 3-segmented club; maximal diameter of eye longer than antennal segment X. Promesonotal dome in dorsal view smooth to shagreened with several weak transverse rugulae, in lateral view with a low mound (as in the holotype) or a conspicuous prominence on its posterior slope; humerus of the dome not produced; the dome at the humeri narrower than at the bottom. Petiole as long as or a little shorter than postpetiole (excluding helcium); petiolar node in lateral view subangulate dorsally; postpetiole massive. First gastral tergite smooth and shining entirely.

Minor. — Frons and vertex smooth and shining; area between antennal insertion and eye with several weak rugulae or weakly rugoso-punctate; preoccipital carina conspicuous dorsally and laterally; median part of clypeus smooth and shining, without a median longitudinal carina; antenna with a 3-segmented club; scape extending far beyond posterolateral margin of head; maximal diameter of eye a little shorter than antennal segment X. Promesonotal dome smooth to shagreened dorsally, and largely smooth laterally; the dome in lateral view with a low or inconspicuous mound on its posterior slope; humeral area of the dome in dorsooblique view neither strongly rugose nor armed with a prominence; mesopleuron, metapleuron and lateral face of propodeum dimly to weakly punctured at least partly. Petiole shorter than postpetiole (excluding helcium); postpetiole massive.

Recognition: This species is characterized by the combination of the following features (see also the recognition of P. rugithorax sp.n.): in the major head in lateral view not impressed on vertex; in the minor frons and vertex smooth and shining; in the major dorsal and lateral faces of vertexal lobe reticulate; in the major frontal carina conspicuous, and antennal scrobe inconspicous or very weak; in the major hypostoma with a low or inconspicuous median process and a pair of low or moderately developed submedian processes, and with conspicuous lateral processes which are located rather ventrally; in the minor promesonotal dome smooth to shagreened dorsally, and largely smooth laterally; in the minor dorsolateral part of the dome neither margined nor armed with a humeral prominence; posterior slope of the dome with a low mound or a conspicuous prominence in the major, and a low or inconspicuous mound in the minor; in the major and minor postpetiole massive.

P. laevithorax is closest to P. rugithorax sp.n. (see under P. rugithorax ). P. laevithorax is also similar to P. noda , but the latter has the following characteristics in the major: head in full-face view rather broadly concave posteriorly; dorsum of head sparsely bearing standing setae which are much longer and distinctly thicker than background hairs (many short decumbent-suberect hairs).

Figures

FIGURE 13a–d, Pheidole laevithorax, holotype (major) [Eg01-VN-230] — 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.