Systematics of the Monomorium rothsteini Forel species complex (Hymenoptera: Formicidae), a problematic ant group in Australia Author Sparks, Kathryn S. South Australian Museum, North Terrace, Adelaide SA 5000, and Australian Centre for Evolutionary Biology and Biodiversity, and School of Earth & Environmental Sciences, The University of Adelaide, 5005, Australia kate.sparks@samuseum.sa.gov.au Author Andersen, Alan N. CSIRO Land and Water Flagship, Tropical Ecosystems Research Centre, PMB 44 Winnellie, NT 0822, Australia Alan.Andersen@csiro.au Author Austin, Andrew D. Australian Centre for Evolutionary Biology and Biodiversity, and School of Earth & Environmental Sciences, The University of Adelaide, 5005, Australia andy.austin@adelaide.edu.au text Zootaxa 2014 2014-12-10 3893 4 489 529 journal article http://dx.doi.org/10.11646/zootaxa.3893.4.2 c50b4017-beb6-4783-820e-8a1da797f2d9 1175-5326 252022 65D00761-21AC-4B5D-ACB9-7BFFC69A75FC Monomorium merepah Sparks , NEW SPECIES ( Fig. 6 g–i, 11 e) Holotype worker . Queensland , Merepah Station , Cape York Peninsular , - 13.585 , 141.8748 , 21 Sep 2011 , A. Andersen , ANA 11–38 (deposited in QM ). Paratypes . Queensland , 5 workers , same data as holotype; 10 workers , Lakefield NP , Welcome Waterhole , 15.2586 , 144.6128 , 10 Aug 2007 , A.L. Hertog , TERC 1 (deposited in MHNG , NMBA , QM , SAM ). Diagnosis. A very large, robust, dark orange species with deeply concave clypeus, strigate frons and sculptured mesonotum. The petiole node is very broad with reticulate sculpture over the entire surface. Worker measurements (n= 9 ). HW 0.82–1.05 , HL 1.01–1.03 , EL 0.16–0.18 , PMH 0.41–0.47 , PH 0.33–0.34 , PNH 0.23–0.25 , LHW 0.6–0.62 , EW 0.11–0.12 , PML 0.66–0.68 , ML 1.09–1.15 , PL 0.49–0.53 , PNWdv 0.27–0.30 . Worker Description. Very large species, with a large, square head; posterior cephalic margin depressed medially. Anterodorsal margin of the clypeus deeply concave, frontolateral carinae forming raised, angular ridges that are produced forward and beyond clypeal anteroventral margin, often with a slightly wavy margin or minute preapical nodules; anteroventral margin without a small median projection, margin appears straight. Frons strigate, strigae extending well above antennal lobes; coarse lateral cephalic strigae reach anterior eye margin. Eyes small, EW < 0.2 x LHW, 12 ommatidia in longest vertical axis, 10 in longest horizontal axis. Mesonotum rugose-strigulate over most of area posteriad of promesonotal suture or sculpture maybe restricted to promesonotal suture, posterior mesonotum and lateral curvature. Most specimens with metanotal area appearing raised with a faint horseshoe shaped margin. Mesopleuron alveolate with a few strigae extending from metanotal groove to promesonotal suture; metanotal groove broad and deep. Propodeum in lateral view with dorsolateral angles almost forming a right angle; laterally alveolate with strigae extending over metapleural gland bulla and radiating dorsally and posteriorly; dorsal surface with transverse anterodorsal carina prominent, longitudinal paired carinae forming irregular convergent lines, transverse strigae present. Petiole node broad, width when viewed from above more than 2.5 x eye width; shape in posterior view tapering from widest point to broadly rounded apex; in lateral view anterior and posterior faces sub parallel, apex broadly rounded from higher anterior face to lower posterior face. Petiole node and postpetiole finely reticulate over entire surface.T 1 finely reticulate on at least anterior half. Head, mesosoma and legs, dark amber orange to orange brown, legs and antennal scapes brown, petiole and postpetiole dorsally infuscated, metasomal tergites dark brown, sternites amber. Distribution. This species is known from two localities on the Cape York Peninsular, Queensland. Its range overlaps with M. capeyork sp. nov. and M. hertogi sp. nov. Etymology. The specific name is a noun in apposition taken from the type locality. Remarks. This is the largest known species in the M. rothsteini complex and is distinguished from all others dealt with here by the petiole node that is entirely sculptured. COI sequences . Genbank accession numbers for this species are KC 572902 and KC 573006 .