Monomorium stagnum

Little is known about the biology of .

Identification
Sparks et al. (2015) - A member of the M. rothsteini species group. A medium sized species with a deeply concave clypeus, strigate frons and sculpture mesonotum. T1 is finely reticulate over anterior half.

Distribution
This species is known from the Kimberley region of Western Australia and far northern areas in the Northern Territory including Melville Island.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Genetics
COI sequences. Genbank accession numbers for this species are KC573011, KC573012, KC573015 and KC573016.

Nomenclature

 *  stagnum. Monomorium stagnum Sparks, in Sparks, Andersen & Austin, 2015: 519, figs. 7j–l, 11f (w.) AUSTRALIA.

Worker
(n=9). HW 0.78–1.01, HL 0.82–0.98, EL 0.16–0.19, PMH 0.29–0.43, PH 0.29–0.35, PNH 0.19–0.23, LHW 0.47–0.59, EW 0.10–0.12, PML 0.51–0.68, ML 0.90–1.09, PL 0.41–0.49, PNWdv 0.21–0.31.

Medium sized species with a medium sized, rectangular head; posterior cephalic margin straight to slightly concave. Anterodorsal margin of the clypeus deeply concave with frontolateral carinae produced anteriorly, extending well beyond anteroventral margin, with acute anterolateral angles and with small, rounded, preapical teeth or nodules; anteroventral margin with or without a small median projection. Frons strigate, extending well above antennal lobes; coarse lateral cephalic strigae reach anterior eye margin. Eyes medium, EW 0.20–0.23 x LHW, number of ommatidia in longest vertical axis, 11 and 9 in longest horizontal axis.

Mesonotum strigulate with shallow alveolae in between strigulae over entire surface posteriad of promesonotal suture or with sculpture restricted to lateral curvature, metanotal groove and posterior mesonotum. Mesopleuron alveolate with a few 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 metapleural gland bulla and extending between spiracle and posterodorsal corner in some specimens; dorsally with prominent transverse anterior ridge and transverse and longitudinal strigae present. Petiole node of moderate width, between 2 and 2.5 x eye width when viewed from above, oval in shape in posterior view, anterior and posterior faces converging to a broadly rounded dorsum in lateral view. Petiole and postpetiole finely reticulate, sculpture not extending onto dorsal surface. T1 finely reticulate, covering at least anterior half of surface.

Head, mesosoma and legs light to dark amber orange, some specimens with mesosoma and legs infuscated, petiole and postpetiole infuscated on dorsal half, metasomal tergites dark brown, sternites amber, hairs dull yellow.

Type Material
Holotype worker. Western Australia, Kimberley Region, Mitchell Falls, site 1, -14.8167, 125.6833, 18 Jul 2007, A. Andersen, TERC11 (deposited in WAM). Paratypes. Western Australia. 20 workers, same data as holotype; 10 workers, Kimberley Region, Mitchell Falls camp, -14.8167, 128.6833, 18 Sep 2007, A. Andersen, TERC21; 9 workers Kimberley Region, Mitchell Falls, -14.2333, 125.6833, 18 Jul 2007, A. Andersen, TERC20; 3 workers, Mitchell Plateau Fire Study, -14.7667, 125.7833, Jun 2007, J. Lanoue, TERC 6 (deposited in NTM,, WAM).

Etymology
The specific name is taken from the Latin word for “pool” and refers to the pools of water that are found at the type locality Mitchell Falls.