Dolichoderus pastorulus

This species shows all characteristics of the typical herdsmen lifestyle. It was always associated with the allomyrmococcine Bolbococcus sabahanus. Biologically, this species differs from most other herdsmen Dolichoderus by the very small size of its colonies and hence its typical small trail systems. (Dill 2002)

Identification
Together with Dolichoderus kinabaluensis and Dolichoderus pilinomas, pastorulus is the species of the Dolichoderus cuspidatus group with the smallest body size. The species is well defined by a combination of several characters, such as size, surface sculpturing, shape of the mesonotum, and especially by the characteristically shaped and high rising propodeum. The dense, ± even punctation of the head is similar to Dolichoderus laotius, Dolichoderus erectilobus, Dolichoderus gibbifer, and pilinomas. Regarding the typical shape of the propodeum, laotius and some specimens of pilinomas are relatively close to pastorulus, although the propodeum of the latter is distinctly steeper and higher ascending. The species appears to be highly variable in its coloration. However, it must be considered that only material from three different locations could be examined. Thus, a sound assessment of the intraspecific variation is not possible. Compared to other species of the cuspidatus group, the queens are less distinctly physogastric. This appears to be clearly correlated to the relatively small colony size of this species. The males have the shortest mandibles of all known males of the species group and are similar, in this respect, to the males of the Dolichoderus thoracicus group.

Distribution
Dill (2002) - Known from the lowland rainforest locations in Sabah, Northeast Borneo. However, this restricted distribution may possibly be caused by the fact that very few collections exist from nearby Kalimantan.

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

Nomenclature

 *  pastorulus. Dolichoderus pastorulus Dill, 2002: 50, figs. III-14, III-22, III-28, III-61 (w.q.m.) BORNEO.

Worker
(Holotype in brackets): HL 1.04-1.51 [1.20]; HW 1.00-1.25 [1.24]; EL 0.24-0.29 [0.27]; SL 0.94-1.12 [1.12]; AL 1.41-1.66 [1.63]; PnW 0.69-0.82 [0.81]; ML 0.39-0.51 [0.45]; MW 0.29-0.41 [0.36]; PpL 0.57-0.73 [0.67]; PpW 0.49-0.61 [0.57]; PpH 0.59-0.76 [0.73]; PpSW 0.35-0.59 [0.52]; HL 0.33-0.41 [0.40]; PtW 0.33-0.47 [0.43]; TL 4.18-5.08 [4.78]. Indices: CI 70- 103 [103]; OI 22-26 [22]; SI 85-98 [91]; MI 105-144 [124]; PpSPpI 72-105 [91]; (n = 35).

Head: From reddish-brown to dark -brown and black, antennae reddish-brown to brownish-black. Entire head evenly, finely and densely punctate (= micro-imbricate. fig. III-63a); matt. Entire head, except of frontal triangle, densely covered by light-yellow pubescence; void of erect hairs. Head suboval or rounded heart-shaped with rounded sides and shallowly emarginate occipital margin; no median superoccipital pits.

Alitrunk: Yellowish-, reddish-, castaneous-, dark-brown or black; legs yellowish, reddish or dark-brown. Entire alitrunk, densely punctate to finely reticulate (= micro-imbricate) and pubescent; erect hairs very scarce and restricted to the ventral face and coxae; mesopleuron, in addition to the fine sculpturing, with coarser irregular reticulate or ± parallel wrinkles (fig. III-63b); lateral face of propodeum finely reticulate. Dorsal face of pronotum flat or weakly arched, its lateral delimination ± indistinct; “shoulders” rounded and indistinct. Mesonotal hump rounded and relatively flat, without a median depression. Propodeum very steeply highly ascending, usually at least as high as long, distinctly overtopping the mesonotumal hump (for at least twice the height of the mesonotum hump itself, fig. III-14b); basal part of ascending face of propodeum laterally rounded, yet distally distinctly edged and widened; its posterior margin medially depressed, its lateral corners expanded to distinct, broad and blunt tips (fig. III-14e); posterior edge overhanging the somewhat concavely curved declivity, which is very finely punctate and shining.

Petiole: Scale very finely punctate; pubescent; entire.

Gaster: Medium-brown, reddish-brown to black. Finely punctate (= micro-imbricate); ± dense, light-yellow pubescense which dorsally merges in a medium line; erect hairs scarce and restricted to ventral face and gaster tip.

Queen
HL 1.19-1.32; HW 1.15-1.25; EL 0.29-0.31; SL 1.04-1.16; AL 1.88-2.06; PnW 0.88-0.96; ML 0.76-0.82; ScL 1.12-1.23; MW 0.64-0.69; MH 0.27-0.35; PpL 0.63-0.73; PpW 0.70-0.75; PpH 0.75-0.82; PpSW 0.39-0.59; PtW 0.51-0.61; TL 5.43-6.14. Indices: CI 95-101; OI 25-27; SI 90-92; MI 118-122; ScI 23-28; PpSPpI 55-77; (n = 6).

Coloration and fine sculpturing as in workers; very densely pubescent. Head similar to that in workers, but more strongly oval and eyes more lateral; occurrence and development of ocelli very variable, in some specimens only an empty pit in place of the anterior ocellus. Alitrunk with the characters typical for the species group; mesonotum hump in profile flatly rounded, only weakly vaulted; no remnants of wing buds or regulae traceable in the examined specimens; propodeum distinctly ascending, but lower rising than in workers and corners less distinctly expanded. Scale of petiole broad, its upper margin not emarginate.

Male
HL 0.76-0.84; HW 1.06-1.12; EL 0.53-0.56; EW 0.41-0.45; SL 0.27-0.29; CL 0.19-0.28; MdL 0.24-0.32; AL 1.59-1.84; PnW 0.80-0.90; ML 1.06-1.22; ScW 0.76-0.86; PpH 0.63-0.75; PtW 0.31-0.33; TL 4.78-5.28. Indices: CI 121-125; OI 49-50; OI2 63-70; OI3 37-41; OI4 50-58; MdI 31-40; MdCpI 107-129; SI 30-33; (n = 10).

Typical Dolichoderus males with the characters of the cuspidatus group, particularly void or erect hairs; dark-brown to black; fine sculpturing as in workers; eyes very large; mandibles in relation to clypeus shorter than in males of other species of the cuspidatus group; scutum distinctly narrower than head.

Type Material
Holotype worker, 2 paratype (BMNH) and 3 paratype workers from same nest: Borneo, Sabah, Poring Hot Springs, Kinabalu NP, 6°04'N, 116°42'E, 25.v.1991 (M. Dill); 3 paratype workers (BMNH), 3 para type workers (MCZ): same location as holotype, 2.vi.1991 (M. Dill); 3 paratype workers (BMNH): same location, 4.vi.1991 (M. Dill); 3 paratype workers (FNMS): same location, 17.vii.1991 (M. Dill); 3 paratype workers (FNMS), 3 paratype workers : same location, 16.vii.1991 (M. Dill); 1 paratype female (BMNH), 1 paratype female (MCZ), 1 paratype female (FNMS): same locality, 17.vii.1991 (M. Dill); 1 paratype female (MCZ), same locality, 17.vi i.1991 (M. Dill); 2 paratype males (BMNH), 2 paratype males (MCZ), 1 paratype males (FNMS): same locality, 16.vii.1991 (M. Dill).

Etymology
Name derived from the diminutive of the Latin “pastor”, meaning “little herdsman”, referring to the lifestyle in connection to the relatively small body size and the small colonies.