Monomorium speculum

Colonies of this species were found in a dry lake bed in central western Australian where workers were observed bearing minute gastropod shells into their nest.

Identification
Sparks et al. (2015) - A member of the M. rothsteini species group. A small, glossy dark brown species with large eyes and a slightly concave to sinuous clypeus. The mesonotum is without sculpture except in the posterior region, the propodeal dorsolateral angles clearly form an obtuse angle or are rounded and the petiole node is narrow.

This species cannot be separated from Monomorium subapterum using morphology alone. Evidence for its separation from M. subapterum comes from a species delimitation study undertaken by (Sparks et al. 2014).

Distribution
This species range covers a large area of southern inland Western Australia.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Genetics
COI sequences. Genbank accession numbers for this species are KC572983, KC572985, KC572986, KC572992 and KC572997.

Nomenclature

 *  speculum. Monomorium speculum Sparks, in Sparks, Andersen & Austin, 2015: 518, figs. 7g–i, 11f (w.) AUSTRALIA.

Worker
(n=9). HW 0.62–0.94, HL 0.68–0.98, EL 0.16–0.2, PMH 0.23–0.35, PH 0.21–0.29, PNH 0.14–0.19, LHW 0.39–0.57, EW 0.11–0.14, PML 0.43–0.60, ML 0.7–0.98, PL 0.31–0.43, PNWdv 0.16–0.21.

Small species with a small, rectangular head; posterior cephalic margin shallowly depressed to broadly v-shaped. Anterodorsal margin of the clypeus concave to sinuous with smooth frontolateral carinae forming ridges that do not extend anteriorly beyond anteroventral clypeal margin; anteroventral margin with or without a median projection. Sculpture on frons limited to a few strigae only present on antennal lobes; coarse lateral cephalic strigae reaching or not reach anterior eye margin. Eyes large, EW > 0.23 x LHW, 12 ommatidia in longest vertical axis, 10 in longest horizontal axis.

Mesonotum without sculpture except for posterior region with a few strigulae extending anteriorly from metanotal groove. Mesopleuron and propodeum alveolate with strigae extending over metapleural gland bulla and reaching metanotal groove. Propodeum in lateral view with dorsolateral angles clearly forming an obtuse angle; dorsal surface with anterior transverse carina absent in a majority of specimens, when present then weakly so; transverse and longitudinal strigae absent, longitudinal depression also absent, dorsolateral angles rounded. Petiole node width when viewed from above less than 2 x eye width; oval shaped in posterior view, when viewed laterally with anterior and posterior faces strongly converging to a narrowly rounded dorsum, posterior surface of petiole node without sculpture, smooth and shining. T1 finely imbricate, covering at least anterior half of surface or completely smooth and without sculpture.

Head, mesosoma and legs light to dark brown, mandibles light brown, antennal scapes and metasoma dark brown to black, cuticle with a high gloss.

Type Material
Holotype worker. Western Australia, Meekatharra, -26.5949, 118.4936, 19 Oct 2009, K.S. Sparks, C. Petit, KSS193 (deposited in WAM). Paratypes. Western Australia. 20 workers, same data as holotype; 20 workers, Lake Annean, 40 km S Meekatharra, -26.8879, 118.2850, 20 Oct 2009, K.S. Sparks, C. Petit, KSS198; 6 workers, KSS199; 5 workers, Niagara Dam, nr Kookynie, -29.4052, 121.4293, 22 Oct 2009, K.S. Sparks, C. Petit, KSS218 (deposited in, , , WAM).

Etymology
The specific name is taken from the Latin word for “mirror” and refers to this species’ highly reflective cuticle.