Taxonomic history
Agosti, 1995 PDF: 433 (q.).See also: Taylor, 1965d PDF: 363; Brown, 1975 PDF: 57; Oliveira & Feitosa, 2019 10.11646/zootaxa.4614.1.3 PDF: 90.Probolomyrmex petiolatus Weber , 1940, Psyche, Comb., Mass. 47, 76, fig. 1, [[ worker ]] Type locality: Barro Colorado Island, Panama Canal Zone. Holotype: N. A. Weber Collection (examined).
The unique holotype worker of this species is illustrated in figures 34 and 35. It has the following dimensions: HL, 0.51 mm.; HW, 0.36 mm.; SL, 0.29 mm.; CI, 71; SI, 81; WL, 0.65 mm.; PW, 0.27 mm.; dorsal petiole width, 0.14 mm.; petiolar node index, 52; petiole height, 0.27 mm.; petiolar node length, 0.23 mm.; lateral petiolar index, 85. Weber's original description adequately characterises this distinctive species. The worker of P. petiolatus differs from that of the sympatric P. angusticeps in its smaller size, with relatively broad head, much shorter scapes, and shorter, more compact petiolar node. The unknown worker of P. boliviensis is undoubtedly similar to P. angusticeps in these features.
Distribution. - Known only from the type locality, Panama: Barro Colorado Island.
Ecology. - The holotype was collected among leaves and humus on the rainforest floor.
petiolatus Weber , 1940: 76. Holotype worker, Panama, Barro Colorado Island [specimen from BCI compared with the type checked by S. Cover].
FEMALE. HL 0.61, HW 0.42, SL 0.44, TL 0.90. CI 70, SI 104, Figures 7, 11 (1 examined).
WORKER. HL 0.51 - 0.64, HW 0.35 - 0.40, SL 0.31 - 0.41, TL 0.66 - 0.88, CI 63 - 69, SI 70, Figures 8, 12 (2 examined).
Comments. This species is easily recognized by the subpetiolar process. The new samples expand the known distribution range well into northern South America. Nothing is known of the biology of this species.
Material examined. 2 workers and 1 female, deposited in MCZ and USNM . PAN- AMA, Barro Colorado Island; leaf litter, forest floor; A. Newton. COLOMBIA , Meta , Quebrada Susamuko , 23 km NW Villavicencio , 1,000 m, leaf litter, March 5, 1972 , J. Peck . VENEZUELA , T. F. Amazonia , Cerro de la Neblina , basecamp, 140 m, 0 ° 50 ' N66 ° 10 ' W , 10 - 20 February 1985 , flight intercept pan trap in rainforest, P. J. Spangler et al .
