Key to Oceanian Proceratium Species

The following key to workers is based on Baroni Urbani, C., de Andrade, M.L. (2003) The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali, Monografie, 36, 1–492.

1

• Petiole triangular and clearly narrowing dorsally in profile (Figs. 126, 127) . . . . . 2

• Petiole rectangular, broad or narrow but never narrowing dorsally in profile (Figs. 131, 150) . . . . . 3

2

return to couplet #1

• Lateral expansions of the frontal carinae broad and widely separated from each other. Head densely punctate (Fig. 126). SI > 76. TL > 4.5 mm. Fiji Islands . . . . . Proceratium relictum

Head of Proceratium relictum worker

Profile of Proceratium relictum worker

• Lateral expansions of the frontal carinae narrow and closer to each other. Head sparsely punctate (Fig. 127). SI < 73. TL < 3.7 mm. Fiji Islands . . . . . Proceratium oceanicum

Head of Proceratium oceanicum worker

Profile of Proceratium oceanicum worker

3

return to couplet #1

• TL ≤ 2.3 mm. Frontal carinae about 1/4 of the head width . . . . . 4

• TL ≥ 2.37 mm; if the TL approaches 2.3 mm (in papuanum TL 2.37-2.59 mm), then the frontal carinae are 1/3 of the head width . . . . . 5

4

return to couplet #3

• Head dorsum and mesosoma strongly reticulate. Mesosoma convex in profile. Colour dark reddish-brown. CI ≥ 100. Papua New Guinea . . . . . Proceratium snellingi

• Head dorsum and mesosoma at most minutely punctate. Mesosoma elongate in profile. Colour black. CI < 96. Papua New Guinea . . . . . Proceratium ivimka

5

return to couplet #3

• Frontal area very broad, at least 1/3 of the maximum head width . . . . . 6

• Frontal area at most 1/4 of the maximum head width . . . . . 7

6

return to couplet #5

• TL < 2.65 mm. Mesosoma, petiole and postpetiole with traces of granulation. Papua New Guinea, Philippines, Sumatra, Malaysia, Sabah and Solomon Islands . . . . . Proceratium papuanum

Head of Proceratium papuanum worker

Profile of Proceratium papuanum worker

• TL > 3.00 mm. Mesosoma, petiole and postpetiole at most minutely punctate. New Caledonia . . . . . Proceratium politum

Head of Proceratium politum worker

Profile of Proceratium politum worker

7

return to couplet #5

• Body smooth and at most with minute piligerous punctures. Petiolar width less than 1 and ½ of the petiolar length. Colour yellow-light brown, legs concolourous. New Caledonia . . . . . Proceratium caledonicum

Head of Proceratium caledonicum worker

Profile of Proceratium caledonicum worker

• Body superficially smooth and at least with punctations and small, sparse granulation. Petiolar width at least 1 and ½ of the petiolar length. Colour dark reddish brown or black with lighter legs. Papua New Guinea . . . . . Proceratium austronesicum

Head of Proceratium austronesicum worker

Profile of Proceratium austronesicum worker