Probolomyrmex maryatiae

Identification
Eguchi et al. (2006) - Four Oriental and Australian species are morphologically very similar to each other: this species, Probolomyrmex greavesi, Probolomyrmex salomonis, and Probolomyrmex vieti. The difference between this species and P. vieti is given in the key. It is separated from P. greavesi as follows: in the worker the petiole in profile has a relatively steep anterior slope and straight posterior outline (above the articulation with gaster). Probolomyrmex maryatiae is barely separated from P. salomonis (holotype worker deposited in MCZC was examined) as follows: in the worker of the former the anterior portion of the subpetiolar process projects strongly and the posterodorsal margin of the petiolar node is relatively broadly concave. In contrast, in the worker of P. salomonis the anteroventral portion of the subpetiolar process forms a round corner and the posterodorsal margin of the petiolar node is relatively narrowly concave.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Indonesia.

Nomenclature

 *  maryatiae. Probolomyrmex maryatiae Eguchi, Yoshimura & Yamane, 2006: 26, figs. 5A-D, 9E, 10E (w) BORNEO.

Worker
HL, 0.54–0.58 mm; HW, 0.35–0.36 mm; SL, 0.33–0.37 mm; CI, 60–67; SI, 92–106; WL, 0.75–0.84 mm; PW, 0.26–0.29 mm; DPtW, 0.16–0.19 mm; DPtI, 61–66; PtH, 0.26–0.29 mm; PtNL, 0.25–0.29 mm; LPtI, 96–104 (N=5). Body ferruginous brown. Head in full-face view with weakly convex sides and very shallowly concave occipital border. Eye absent. Antenna relatively short; relative lengths of antennal segments II–XII as seen in Fig. 10E; antennal segment III shorter than IV. Dorsal outline of mesosoma almost straight; posterior margin of propodeal dorsum in dorsal view strongly concave; posterior face of propodeum margined laterally with a well-developed translucent lamella which in profile forming an obtuse angle in upper portion. Petiole including subpetiolar process as long as or a little longer than high, in profile with relatively gentle anterior slope and (weakly) concave posterior outline (above the articulation with gaster); posterodorsal margin of petiolar node in dorsal view weakly and broadly concave; subpetiolar process developed, with conspicuous anteroventral and posteroventral projections; the anteroventral projections relatively thick and not translucent. Abdominal segment III (gastral segment I) in profile relatively short, relatively gently narrowed anteriad in the anterior 3/4; abdominal sternum III weakly convex behind the midlength.

Type Material
Holotype: worker belonging to colony Eg97-BOR-587, Gunong Rara, Sabah, Malaysia, 25/ii/1997, Eg. Paratypes: 4 workers from the same colony to which the holotype belongs.