Probolomyrmex dammermani Wheeler

Eguchi, K., Yoshimura, M. & Yamane, S., 2006, The Oriental species of the ant genus Probolomyrmex (Insecta: Hymenoptera: Formicidae: Proceratiinae)., Zootaxa 1376, pp. 1-35 : 5-9

Probolomyrmex dammermani Wheeler

(Figs. 1A-F, 9A, 10A, 11A-E, 15A, B, 16A-C)

Probolomyrmex dammermani Wheeler , 1928: 7-9, fig. 1. [Taylor, 1965: 356-358, figs. 17-19 (revision of the genus); Ito et al., 2001: 403 (species list).] Syntypes: 4 workers, Buitenzorg [Bogor] , Java, Indonesia, 18/xii/1922, K. Dammerman ( MCZC) [one worker examined].

Nontype material examined. VIETNAM: Nghe An: Sang Le Forest, Tuong Duong [ colony: Eg 01iv 06-08 ] ; INDONESIA: W. Java: Kebun Raya Bogor [general coll.: FI, Jan/ 1993; colony: FI95-517 (including queen & male), FI95-558 , FI95-591 (including male), FI95-717 (including queen & male), FI97-45 , JV04-SKY-12 (including queen)] , Peucang Isl., Ujung Kulon N. P. [ colony: FI97-117 ] , Pasir Pugog, Pangandaran N. P. [ colony: Eg 12v 06-16 ] ; C. Java: Kuwalahan (plantation at 800 m alt.) [general coll.: E. Kaufmann et al.: No. 74 , 3/xii/2000] ; W. Bali: Sumber Lampok, Geroka, Buleleng, Bali Barat N. P. [ colony: Eg 26v 06-04 (including queen)] , Dusun PK Jelati, Mendaya [general coll.: SKY, 5- 6/v/1998] ; PHILIPPINES: Negros Or.: Chapman's Gard., Valencia, Dumaguete [general coll.: V. Samarita, 29/xii/1998] .

Worker. HL, 0.54-0.66 mm; HW, 0.35-0.42 mm; SL, 0.31-0.49 mm; CI, 63-67; SI, 89-117; WL, 0.69-0.96 mm; PW, 0.26-0.34 mm; DPtW, 0.15-0.19 mm; DPtI, 55-59; PtH, 0.21-0.26 mm; PtNL, 0.23-0.34 mm; LPtI, 110-131 (N=7).

Queen (alate and dealate queens). HL, 0.61-0.66 mm; HW, 0.42-0.44 mm; SL, 0.40-0.49 mm; EL, 0.11-0.13 mm; CI, 67-70; SI, 93-111; EI, 26-30; WL, 0.91-1.02 mm; PW, 0.37-0.38 mm; DPtW, 0.20 mm; DPtI, 53-54; PtH, 0.26-0.28 mm; PtNL, 0.30-0.33 mm; LPtI, 115-127 (N=3, but N=2 for DPtW and DPtI). Body ferruginous brown. Head in full-face view elongate, with very weakly convex sides and almost straight occipital border. Eye a little shorter than the width of apical antennal segment. Antennal scape when laid backward reaching or a little extending beyond the level of posterior margin of median ocellus; relative lengths of antennal segments II-XII as in the worker (see Fig. 10A); segment III almost as long as IV. Pronotum large; mesoscutum ca. 1.1-1.2 times as long as broad, in profile weakly convex; notauli absent; parapsidal lines very fine; scutoscutellar suture fine, very weakly and roundly curved posteriad; scutellum in profile with relatively 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 weak depression present dividing metepisternum into anepisternum and katepisternum; orifice of metapleural gland small, opening posterolaterad; posterior margin of propodeal dorsum in dorsal view moderately and broadly concave; posterior face of propodeum margined laterally with a well-developed translucent lamella which in profile forms an angle in upper portion. Petiole including subpetiolar process longer than high, in profile with very 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 almost straight or very weakly convex; subpetiolar process low, with an acute anterior projection and posteriorly with a low and sometimes obtusely angulate prominence. Abdominal segment III (gastral segment I) in profile relatively short, gently narrowed anteriad in the anterior 3/4 (in the queen from Bali the segment in profile a little slenderer). Wing structure and venation as in the male. Hind wing with three hamuli.

Male. HL, 0.46-0.47 mm; HW, 0.46-0.47 mm; CI, 98-102; HD, 0.38-0.41 mm; HDI, 83-87; EL, 0.23-0.24 mm; SL, 0.30-0.32 mm; SI, 64-68; MstlL, 0.20-0.22 mm; MstlW, 0.20-0.23 mm; MstlI, 95-110; WL, 0.95 mm; PtNL, 0.28-0.32 mm; PtH, 0.16-0.20 mm; LPtI, 155-175 (N=3 but N=1 for WL). Head in lateral view relatively thin (HDI<90); protrusion of the frontoclypeal region relatively long, so that antennal insertion situated in the middle of its dorsal surface. Frontal carina low, not or slightly exceeding posterior margin of antennal insertions in full-face view. Eye relatively narrow, weakly widened ventrally. Antennal flagellum relatively long, filiform, with antennal segment III distinctly longer than segment II; segment XI (the third from apex) distinctly longer than broad; ventrolateral surface of the apical segment not concave. Mandible elongated triangular, with only a single strong apical tooth on its masticatory margin; basal angle distinct. Palpal formula: maxillary 4, labial 2; maxillary palp moderately long; the third palpomere distinctly longer than the second, and the apical distinctly longer than the third. With the mesosoma in lateral view, pronotum distinctly higher than mesoscutum; metanotum strongly produced posteriorly, and a suture separating it from mesoscutellum strongly notched; anepisternum of metapleuron separated from metakatepisternum and propodeum by a deep furrow; a suture between metakatepisternum and propodeum weak, but separation between the plates recognizable; dorsal margin of propodeum forming an angle with posterior slope. With the mesosoma in dorsal view, mesonotum lacking notauli; parapsidal lines distinct; axillae distinct; mesoscutellum slightly broader than long; declivitous face of the propodeum very slightly concave with weak, obtuse lateral lamellae. Petiole in lateral view without a distinct peduncle; node long with gentle anterior slope and steep posterior slope; posterodorsal margin angular; subpetiolar process narrowly developed with its apex sharp. Abdominal sternum IX long, with its apical margin gently pointed medially. Genitalia retractile. With the phallus in lateral view, the basal ring moderately long and its dorsal margin gently declined; dorsal margin of the basiparamere gently raised in its basal portion; posterodorsal slope gentle; digitus volsellaris simply curved ventrally in its apical portion; penis valve relatively thick and nearly straight, not strongly narrowed apically, and its apical portion blunt and slightly curved ventrally. Paramere thin; its expanded inner faces directed ventrally, of which apical portion is curved dorsally. Aedeagal apodeme relatively narrow. On fore wing, costa and radius apical to stigma vestigial; Rsf2 and Rsf3 completely absent; radial sector never reaching costal margin; Mf1, Rs+M and media apical to Rs+M present; cu-a cross vein present. On hind wing, Rsf4+5 present; jugal lobe absent.

Recognition. The nontype workers agree with the syntype worker. However, a certain variation is seen in the following characters: punctation on the body surface; convexity of lateral outlines of head in full-face view; concavity of occipital border (also mentioned by Taylor, 1965); development of posterior portion of subpetiolar process (also mentioned by Taylor, 1965); and development of posterolateral lamella of propodeum (sometimes forming a triangular propodeal spine). The flagellum is more slender in the worker and queen from Bali than in those from the other localities. Workers from colony Eg01iv06-08 are smaller, antennal scape shorter, and petiole in profile shorter (N=2; WL 0.69-0.73 mm, SI 89, LPtI 110) than in the material from the other localities (N=5; WL 0.88-0.96 mm, SI 103-117, LPtI 116-131).

In the worker this species is most similar to P. longinodus , but well distinguished from the latter by the relatively shorter petiole (LPtI <135) and poorly developed propodeal teeth in the worker (see also Terayama & Ogata, 1988). In the male, P. dammermani is similar to P. longiscapus and P. longinodus , but the former can be separated from the latter two by the following characters: 1) thinner head in lateral view, 2) lower frontal carina, 3) narrower eye, and 4) narrower abdominal sternum IX and genitalia.

Distribution. Known from M. Vietnam, Java and Bali (Indonesia), and Negros (Philippines).