Comprehensive DescriptionRead full entry
Probolomyrmex brevirostris (Forel) HNS , comb. n. (figs. 13 - 16)
Escherichia brevirostris Forel HNS , 1910, Zool. Jahrb. Syst. 29: 246 - 7, [[ worker ]] Type locality: Ghinda, Eritrea. Holotype: Forel coll., Museum d'Histoire Naturelle, Geneva (examined).
Synonymy. - A direct comparison of the holotype with that of Probolomyrmex parvus Weber HNS (1949, Amer. Mus. Nov. 1398: 3, fig. 2, [[ queen ]]; type locality: Busnia, Uganda; holotype: American Museum of Natural History) leaves little doubt that parvus HNS is a synonym; the question is discussed below, and only the difference in caste between the two holotypes prevents a formal establishment of synonymy.
HL, 0.51 mm.; HW, 0.34 mm.; SL, 0.27 mm.; CI, 67; SI, 79; WL, 0.59 mm.; PW, 0.25 mm.; dorsal petiole width, 0.15 mm.; petiolar node index, 60; petiole height, 0.28 mm.; petiolar node length, 0 - 20 mm.; lateral petiolar index, 71. General features as in figures 13 and 14 and in the original description.
This species is apparently unique in Probolomyrmex HNS in the possession of well developed compound eyes in the worker. Those of the holotype are about 0.05 mm. in maximum diameter, with about 14 facets. Their anteriormost points are situated approximately 2.3 times their maximum diameter from the lateral base of the frontoclypeal shelf. It is possible that the holotype is not normal for this character, for it could be a worker-queen intermediate. There is no compelling reason to assume this, however, and the specimen is provisionally accepted as a typical worker. In any case the synonymy of parvus HNS and the distinctiveness of this species in Probolomyrmex HNS would not be jeopardised if the worker was found to be normally eyeless, and such a discovery could only support the synonymy of Escherichia HNS under Probolomyrmex HNS .
The entire body is moderately finely shagreened and there is no trace of an accompanying coarse puncturation. Pilosity and pubescence as in filiformis HNS .
(Based on the holotype of parvus HNS , a dealated specimen.) HL, 0.50 mm.; HW (behind eyes), 0.35 mm.; SL, 0.27 mm.; CI, 70; SI, 77; WL, 0.67 mm.; mesonotal width, 0.28 mm.; dorsal petiole width, 0.16 mm.; petiole height, 0 - 26 mm.; petiolar node length, 019 mm.; lateral petiolar index, 73. General features as in figures 15 and 16. Differing from the worker in the usual characters. Maximum diameter of compound eyes, 0.11 mm. Form of head, mandibles and petiolar node almost exactly as in worker. Mesosomal structure complete. Sculpturation, pilosity and pubescence developed similarly to those in worker; ground colour slightly darker reddish-brown, eyes dark brown, almost black, each ocellus with an adjacent dark brown spot, suture lines of mesosoma infuscated.
The oral palpi are not visible in the worker, but the general form of the three apical maxillary and the terminal labial palpomeres of the queen is normal for the genus. The terminal maxillary segment is about 5 times as long as broad.
Biology. - The holotype bears a label reading " bei termiten ". Weber's queen was taken " among humus and leaves at the base of a tree with a few bushes forming an island in a banana plantation. "