Monomorium mitchell Sparks

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, Zootaxa 3893 (4), pp. 489-529 : 514

Monomorium mitchell Sparks , NEW SPECIES

( Fig. 6 j–l, 11e)

Holotype worker. Western Australia, Kimberley Region, Mitchell Falls , -14.8167, 125.6833, 18 Jun 2007, A. Andersen, TERC17 (deposited in WAM).

Paratypes. Western Australia, 20 workers, same data as holotype, 20 workers, same data as holotype, TERC18 (deposited in NTM, SAM, WAM).

Diagnosis. Large, dark orange species with a concave clypeus, strigate frons and sculptured mesonotum. The head is narrowed behind the eyes and dorsolateral angles of the propodeum almost form a right angle, giving the propodeum a cuboid appearance.

Worker measurements (n=9). HW 0.80–0.94, HL 0.94–0.96, EL 0.19–0.2, PMH 0.37–0.39, PH 0.29–0.33, PNH 0.23–0.25, LHW 0.57–0.59, EW 0.12–0.14, PML 0.66–0.68, ML 0.99–1.11, PL 0.43–0.49, PNWdv 0.27–0.31.

Worker Description. Large species with a medium sized, rectangular head; posterior cephalic margin straight to shallowly depressed medially; head distinctly narrowed behind eyes. Anterodorsal margin of the clypeus concave with frontolateral carinae forming angular ridges that extend just beyond anteroventral clypeal margin forming obtuse angles. Sculpture on frons strigate, extending well above antennal lobes; coarse lateral cephalic strigae reach anterior eye margin. Eyes medium, EW 0.20–0.23 x LHW, 13 ommatidia in longest vertical axis, 11 in longest horizontal axis.

Mesonotum alveo/strigulate over most of area posteriad of promesonotal suture, a small central area without sculpture. Metanotal groove broad and deep. Mesopleuron alveolate, strigae extending less than half way on to mesopleuron from both promesonotal suture and metanotal groove, a few irregular strigulae on ventral third. Propodeum in lateral view with dorsolateral angles almost forming a right angle, propodeum appears cuboid. Propodeum alveolate, laterally with strigae extending over metapleural gland bulla and reaching metanotal groove, between metanotal groove and spiracle, extending on to dorsal surface and on lateral face of posterodorsal corners; dorsal surface with anterodorsal transverse carina weekly present, transverse strigae present longitudinal strigae present as several irregular lines, dorsal concavity restricted to posterior half, anterior half rounded. Petiole node of medium breadth, between 2 and 2.5 x eye width when viewed from above, shape in posterior view tapered from widest point to rounded apex, in lateral view with anterior and posterior faces sub parallel, apex broadly rounded from higher anterior face to lower posterior face. Petiole and postpetiole finely reticulate laterally and basally, smooth dorsally. T1 finely reticulate on at least anterior half of surface.

Head, mesosoma and legs dark orange brown, antennal scapes dark brown, petiole and postpetiole dorsally infuscated, metasoma dark brown except T1 medially infused with amber, sternites amber.

Distribution. This species is known only from the Mitchell Falls in the Kimberley region of Western Australia. Its range overlaps with M. stagnum sp. nov.

Etymology. The specific name is a noun in apposition taken from the type locality.

COI sequences. Genbank accession numbers for this species are KC573013 and KC573014 .

Figures

FIGURE 6. Workers of the M. rothsteini (Forel) species complex in lateral, head and dorsal view of the mesosoma. Fig. 6 a – c: M. leda, lectotype (Kimberley District, WA), d – f: M. maryannae holotype (Berry Springs, NT, ANA 09 – 15), g – i: M. merepah, paratype (Lakefield NP, QLD, TERC 1), j – l: M. mitchell, holotype (Mitchell Falls, WA, TERC 17), m – o: M. oodnadatta, holotype (160 km E Mala, SA, KSS 114). Scale bars are 0.5 mm for all views.