Key to Australian Proceratium Species

The following worker key to Australian Proceratium is based on Baroni Urbani & de Andrade (2003).

1

• Petiolar node low and rounded; leading edge of clypeus projecting forward and the insertions of the antennae well back from the edge => 2

• Petiolar node high and box-like; leading edge of clypeus straight and the insertions of the antennae very close to the edge => 3

2

• Postpetiole concave medially and gently lobate laterally; erect hairs on sides of head sparse and short (length less than the maximum width of the scape) => Proceratium cavinodus

Head of Proceratium cavinodus worker

Profile of Proceratium cavinodus worker

• Postpetiole flat medially and convex laterally; standing hairs on the sides of head abundant and long (length greater than the maximum width of the scape) => Proceratium stictum

Head of Proceratium stictum worker

Profile of Proceratium stictum worker

3

• When viewed from above, petiole more than 1.5 times wider than long; smaller, total length less than 2.63mm => Proceratium pumilio

Head of Proceratium pumilio worker

Profile of Proceratium pumilio worker

• When viewed from above, petiole at most 1.5 times wider than long; almost always larger (total length greater than 2.64mm, if smaller then PeW less than 0.27mm) => 4

4

• Erect hairs on body long; scapes relatively long (SI greater than 0.73) => Proceratium hirsutum

Head of Proceratium hirsutum worker

Profile of Proceratium hirsutum worker

• Erect hairs on body short; scapes relatively short (SI less than 0.70) => 5

5

• Postpetiole smooth or at most with very weak sculpturing => 6

• Postpetiole with strong and dense sculpturing => 7

6

• Central region of leading edge of clypeus projecting forward of the lateral regions; long hairs on gaster sparse and suberect; head relatively long and narrow (cephalic index less than 0.93), the scape relatively long (scape index greater than 0.68) => Proceratium gracile

Head of Proceratium gracile worker

Profile of Proceratium gracile worker

• Leading edge of clypeus essentially flat across its entire width; long hairs on gaster denser, subdecumbent and decumbent; head broader and nearly square (cephalic index more than 0.94), the scape relatively short (scape index less than 0.65) => Proceratium robustum

Head of Proceratium robustum worker

Profile of Proceratium robustum worker

7

• Mesosoma strongly convex in profile, the propodeum lower than the mesonotum and rounded; propodeal sides with a tooth; head relatively narrow (cephalic index less than 0.85), the sides more or less parallel; body larger (total length about 3.72mm) => Proceratium gigas

• Mesosoma more elongate, the propodeum only slightly lower than the mesonotum and its dorsal face flatter; propodeal sides at most denticulate; head relatively wide (cephalic index greater than 0.89), the sides tapering inwards towards the mandibles; body smaller (total length less than 3.5mm) => Proceratium australe

Head of Proceratium australe worker

Profile of Proceratium australe worker