Monomorium hoffmanni Sparks, NEW SPECIES (Fig. 5 g–i, 11f) Holotype worker. Northern Territory. VRD, Mt Stanford Station, -16.9607, 130.5383, 12 Jul 2008, A.N. Andersen, TERC70 (deposited in NTM) Paratypes. Northern Territory. 10 workers, same data as holotype; 4 workers, Pigeon Hole Stn. Victoria River Downs, -16.3345, 131.1087, May 2007, A. Fisher, ANA09-16 (deposited in NTM, SAM). Diagnosis. A medium sized, amber orange species with a concave clypeus with carinae that extend beyond the clypeal anteroventral margin, which in most specimens has a small median projection; the mesonotum is almost entirely smooth. Worker measurements (n=9). HW 0.76–0.99, HL 0.8–0.98, EL 0.16–0.2, PMH 0.29–0.45, PH 0.25–0.33, PNH 0.2–0.23, LHW 0.49–0.60, EW 0.11–0.13, PML 0.43–0.68, ML 0.78–1.11, PL 0.39–0.51, PNWdv 0.21–0.31 Worker Description. Medium sized species with a large, square head; posterior cephalic margin shallowly depressed to broadly v shaped; head clearly more broad above eyes than below. Anterodorsal margin of the clypeus concave with angulate frontolateral carinae that extending beyond anteroventral clypeal margin forming an obtuse angle; anteroventral margin with a small median projection. Sculpture on frons strigate, restricted to antennal lobes and area in between; coarse lateral cephalic strigae reach anterior eye margin. Eyes medium, EW 0.20–0.23 x LHW, 12 ommatidia in longest vertical axis, 9 in longest horizontal axis. Mesonotum almost entirely smooth, a few strigulae on posterior and lateral portions of posterior mesonotum. Mesopleuron alveolate with one or two strigae extending anteriorly from metanotal groove. Propodeum in lateral view with dorsolateral angles clearly forming an obtuse angle, sculpture alveolate, laterally with strigae extending over metanotal gland bulla and reaching metanotal groove and extending from gland bulla on to posterior surface; dorsal surface with anterodorsal transverse carina and transverse strigae weakly present, longitudinal strigae very weekly present as a broken lines on posterior half only, posterolateral corners carinate, extending from metapleural lobe almost to dorsal surface. Petiole node of medium breadth, between 2 and 2.5 x eye width when viewed from above; shape in posterior view tapering from widest point to narrowly rounded apex, in lateral view with anterior and posterior face converging, apex broadly rounded from higher anterior face to lower posterior face; posterior surface finely reticulate laterally and basally but not extending more than half way to dorsal surface or rarely without sculpture, smooth and shining, postpetiole finely reticulate over most of surface excluding dorsum. T1 finely reticulate covering at least anterior third of surface or rarely completely smooth and without sculpture. Head and mesosoma amber orange, to orange brown, antennal scapes and legs brown, petiole and postpetiole dorsally infuscated, metasomal brown, of a similar tinge to petiole node, sternites amber. Distribution. This species is known only from the Victoria River District of the Northern Territory. Its range overlaps with M. geminum sp. nov. / M. topend sp. nov., M. kidmani sp. nov. and M. subapterum. Etymology. This species is named in honour of Ben Hoffmann, who has spent many years collecting ants throughout Australia. COI sequences. Genbank accession numbers for this species are KC572868 and KC573023.

Published as part of Sparks, Kathryn S., Andersen, Alan N. & Austin, Andrew D., 2014, Systematics of the Monomorium rothsteini Forel species complex (Hymenoptera: Formicidae), a problematic ant group in Australia, pp. 489-529 in Zootaxa 3893 (4) on pages 506-507, DOI: 10.11646/zootaxa.3893.4.2, http://zenodo.org/record/252022