Monomorium pilbara 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 : 515-517

Monomorium pilbara Sparks , NEW SPECIES

( Fig. 7 a–c, 11e)

Holotype worker. Western Australia, 4km S Newman, -23.3657, 119.7839, 19 Oct 2009, K.S. Sparks, C. Petit, KSS188 (deposited in WAM)

Paratypes. Western Australia. 20 workers, same data as holotype, 4 ergatoids, 21 workers, Tom Price Caravan Park, -22.6976, 117.7615, 16 Oct 2009, K.S. Sparks, C. Petit, KSS168; 11w, same locality and collectors, 17 Oct 2009, KSS171; 11 workers, KSS173; 24 workers, 10km N Tom Price, -22.6019, 117.7457, 17 Oct 2009, K.S. Sparks, C. Petit, KSS178 (deposited in NTM, SAM, WAM).

Diagnosis. A medium sized, amber orange species with a concave clypeus and a median projection on the anteroventral clypeal margin. Transverse and longitudinal strigae are absent from the dorsal surface of the propodeum, and the petiole node is narrow.

Worker measurements (n=9). HW 0.78–0.94, HL 0.84–0.88, EL 0.16–0.18, PMH 0.29–0.37, PH 0.25–0.29, PNH 0.18–0.23, LHW 0.45–0.57, EW 0.11–0.12, PML 0.49–0.59, ML 0.82–0.99, PL 0.37–0.45, PNWdv 0.18–0.23.

Worker Description. Medium sized species with a medium sized, rectangular head; posterior cephalic margin very broadly v shaped to shallowly concave. Anterodorsal margin of the clypeus concave with frontolateral carinae extending beyond anteroventral clypeal margin but not forming acute angles and without preapical teeth, most specimens with frontolateral carinae with a wavy margin. Anteroventral margin of the clypeus with a small median projection. Frons with strigae extending well above antennal lobes in some specimens or 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 strigulate on lateral curvature, in metanotal groove and extending onto posterior mesonotum, smooth medially; posterior mesonotum appears raised with a faint horseshoe shaped margin in some specimens. Mesopleuron alveolate, without strigae. Propodeum in lateral view with dorsolateral angles clearly forming an obtuse angle, sculpture laterally alveolate with a few strigae extending over metapleural gland bulla only; anterodorsal transverse carina present; transverse and longitudinal strigae absent. Petiole node narrow, width when viewed from above less than 2 x eye width; oval shaped in posterior view, in lateral view sub parallel sided and broadly rounded from higher anterior margin to lower posterior margin. Petiole node finely reticulate laterally and basally but not extending more than half way to dorsal surface, postpetiole faintly reticulate laterally and along posterobasal margin. T1 with fine reticulate sculpture over anterior quarter only.

Head and mesosoma light to dark amber orange, legs orange brown, petiole and postpetiole infuscated on dorsal half, metasoma dark brown, hairs dull yellow.

Distribution. This species is known only from the Pilbara region of Western Australia. Its range overlaps with M. subapterum and M. tenebrosum sp. nov.

Etymology. The specific name is a noun in apposition taken from the region in Western Australia where this species has been collected.

Remarks. This species has so far only been found in the Pilbara region of Western Australia. Several ergatoidlike females have been collected foraging with workers outside a nest at Tom Price. These specimens are somewhat larger, with a well-defined promesonotal suture, scutellum and coarser sculpture but otherwise closely resemble the workers.

COI sequences. Genbank accession numbers for this species are KC572977 – KC572979 and KC572981 – KC572982 .

Figures

FIGURE 7. Workers of the M. rothsteini (Forel) species complex in lateral, head and dorsal view of the mesosoma. Fig. 7 a – c: M. pilbara, holotype (4 km S Newman, WA, KSS 188), d – f: M. rothsteini, (Alice River, QLD, ES 38), g – i: M. speculum paratype (Niagara Dam, WA, KSS 218), j – l: M. stagnum, holotype (Mitchell Falls, WA, TERC 11), m – o: M. subapterum, (160 km E Mala, SA, KSS 116). Scale bars are 0.5 mm for all views.