Probolomyrmex itoi, Eguchi, K., Yoshimura, M. & Yamane, S., 2006

Eguchi, K., Yoshimura, M. & Yamane, S., 2006, The Oriental species of the ant genus Probolomyrmex (Insecta: Hymenoptera: Formicidae: Proceratiinae)., Zootaxa 1376, pp. 1-35 : 9-13

Probolomyrmex itoi sp. nov.

(Figs. 2A-F, 9B, 10B)

Type material. Holotype: worker belonging to colony FI92-153 , Sitiung , W. Sumatra, Indonesia, 7/i/1992, FI ( MZB). Paratypes: 3 workers and a queen from the same colony to which the holotype belongs ( MCZC, MHNG, SKYC).

Nontype material examined. MALAYSIA: Sarawak: Lambir N. P., Miri [general coll.: Eg, 23/vi/1998]. INDONESIA: W. Sumatra: Ulu Gadut, Padang [ FI97-510 ].

Eguchi's informal species code " Probolomyrmex sp. eg-5" and Yamane's " Probolomyrmex sp. 2" apply to this species.

Worker. HL, 0.76-0.80 mm; HW, 0.42-0.48 mm; SL, 0.76-0.81 mm; CI, 55-60; SI, 165-186; WL, 1.18-1.30 mm; PW, 0.38-0.41 mm; DPtW, 0.19-0.22 mm; DPtI, 50-54; PtH, 0.23-0.28 mm; PtNL, 0.41-0.47 mm; LPtI, 168-178 (N=5). Body ferruginous brown; area where eye is located in the queen pale colored; mandible entirely yellow; legs paler; apical gastral segments yellowish. Head in full-face view extremely elongate, with weakly convex sides; occipital border almost straight or very shallowly concave. Eye absent. Antennal scape when laid backward slightly extending beyond occipital border; relative lengths of antennal segments II-XII as in Fig. 10B; segment III as long as or a little longer than IV. Promesonotum in profile very weakly convex; posterior margin of propodeal dorsum in dorsal view deeply concave; posterior face of propodeum margined laterally with a carina which forms a triangular propodeal spine at upper portion. Petiole including subpetiolar process much longer than high, in profile with weakly concave posterior outline (above the articulation with gaster); posterodorsal margin of petiolar node in dorsal view almost straight or with a shallow median emargination; subpetiolar process inconspicuous, only with an acute anterior projection. Abdominal segment III (gastral segment I) in profile slender, gently narrowed anteriad in the anterior 3/4).

Queen (dealate queen). HL, 0.75 mm; HW, 0.47 mm; SL, 0.74 mm; EL, 0.15 mm; CI, 63; SI, 157; EI, 32; WL, 1.23 mm; PW, 0.43 mm; DPtW, 0.19 mm; DPtI, 44; PtH, 0.25 mm; PtNL, 0.44 mm; LPtI, 176 (N=1). Body ferruginous brown; antennae and legs paler. Head in full-face view elongate, with weakly convex sides and almost straight occipital border. Eye slightly longer than the width of apical antennal segment. Antennal scape when laid backward extending beyond the level of posterior margin of lateral ocelli and nearly reaching occipital border; relative lengths of antennal segments II-XII as in the worker; segment III a little longer than IV. Pronotum large; mesoscutum ca. 1.3 times as long as broad, in profile very weakly convex; notauli absent; parapsidal lines fine but distinct; scuto-scutellar suture fine, very weakly and roundly curved posteriad; scutellum in profile with steep posterior slope; axilla poorly separated from scutellum by an obscure impression but not by a suture; mesopleuron (except in its posteriormost part) well divided by a suture into anepisternum and katepisternum; raised median area of metanotum with gentle lateral slopes; suture between metepisternum and propodeum absent; a deep depression present dividing metepisternum into anepisternum and katepisternum; orifice of metapleural gland small, opening posteriad; posterior margin of propodeal dorsum in dorsal view deeply concave; posterior face of propodeum margined laterally with a lamella which forms a triangular propodeal spine at upper portion; outline from propodeal spine to propodeal lobe in profile weakly concave. Petiole including subpetiolar process much longer than high, in profile with a extremely long, flattened dorsal outline and weakly concave posterior outline (above the articulation with gaster), in dorsal view gradually widened toward the midlength and parallel-sided in posterior half; posterodorsal margin of petiolar node in dorsal view truncated medially; subpetiolar process inconspicuous, only with an acute anterior projection. Abdominal segment III (gastral segment I) in profile slender, relatively gently narrowed anteriad in the anterior 4/5; abdominal sternum III in profile only weakly convex in front of its posterior end.

Recognition. This species is similar to P. longiscapus Xu et Zeng, but SI and LPtI are much greater in the worker and queen of P. itoi than in those of P. longiscapus .

Distribution. Known only from Borneo and Sumatra.