A rare ant on Samoa: first record of the cryptic subfamily Proceratiinae (Hymenoptera, Formicidae) and description of a new Proceratium Roger species

Abstract

In this study we present a taxonomic update for the Oceanian Proceratium. A recent ant biodiversity survey in Samoa collected an unknown Proceratium species, which we describe here as Proceratium silisili sp. n. This new species also presents the first record of this genus, as well as the whole subfamily Proceratiinae, in Samoa. Proceratium silisili is clearly distinguishable from the other Oceanian Proceratium species based on the differences in petiole node shape, number of mandible teeth, shape of the abdominal segment IV, as well as the surface sculpture on the head. A detailed description of P. silisili, high-quality specimen images, as well as an identification key to Oceanian species and a diagnostic discussion are provided.