Aenictus acerbus sp. n. (Figs 1-3, 7, 8, 24) Types. Holotype worker from 9km ENE Mt. Tozer, 12°43'S 143°17'E, Queensland, 5-10 July 1986, J.C.Cardale, ex. pan traps (ANIC, ANIC 32-023688). Two paratype workers, same data as holotype (ANIC, ANIC 32-023646). Diagnosis. Head capsule entirely smooth and essentially uniformly coloured; scape relatively short (SI 0.62mm). This species is morphologically similar to A. turneri but can be separated from it by its larger size and more extensive sculpturing on the pronotum. Worker Description. Mandible narrow and subtriangular, with a large apical tooth and a smaller subapical tooth followed by 4-6 small teeth and a larger basal tooth; anterior clypeal border varying from weakly convex to weakly concave, located at or slightly posterior to anterior margin of frontal lobes in full face view; parafrontal ridges absent; subpetiolar process a large rectangular to elongate-rectangular projection; head entirely smooth, pronotum with weak, closely spaced punctures dorsally and anteriorly, smooth posterolaterally, remainder of mesosoma finely punctate with weak longitudinal rugae on lateral surfaces; body yellow-red to light red-brown. Measurements. Worker (n = 13) - CI 88-97; HL 0.66-0.73; MTL 0.59-0.67; HW 0.62-0.66; ML 1.07- 1.17; SI 81-91; SL 0.53-0.58. Additional material examined. Australia: Northern Territory: Douglas Daly, CRC Clay Site A5 (Salvarani,A.) (TERC); Douglas Daly, CRC Clay Site A8 (Salvarani,A.) (TERC); PWCNT, Tiwi Island Fauna Survey FR (Woinarski,J.) (TERC); Solar Village Survey, Burnt Slope 3 (Andersen,A.N.) (TERC). Queensland: 9km ENE Mt. Tozer (Cardale,J.C.) (ANIC). Western Australia: Kimberley, CALM Site 4/3 (Weir,T.) (TERC). Comments. This rare species is known from a limited number of collections in the Kimberley region of Western Australia, northern Northern Territory and on Cape York Peninsula, Queensland. All specimens were collection from pitfall traps or pan traps. It is very similar to A. turneri but the differences outlined above under Diagnosis seem to hold for all currently available specimens and it is here recognised as a separate taxon.

Published as part of Shattuck, S. O., 2008, Review of the ant genus Aenictus (Hymenoptera: Formicidae) in Australia with notes on A. ceylonicus (Mayr)., pp. 1-19 in Zootaxa 1926 on page 4