Monomorium leda Forel 1915

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 : 510-512

Monomorium leda Forel 1915 , stat. rev., stat. nov.

( Fig. 6 a-c, 11d)

Monomorium rothsteini var. leda Forel 1915:71 –72 .

1 worker, Western Australia, Kimberley District, [E.G] Mjöberg ( MHNG), here designated as the lectotype.

16 workers, same data as lectotype (14 in MHNG; 2 in ANIC), here designated as paralectotypes. Lectotype and these 16 paralectotypes used for the concept of this species, redescribed below.

Other paralectotypes: 5 workers, Alice River , Queensland (3 MHNG; 2 ANIC); 5 males, same data as lectotype ( MHNG). These 5 worker paralectotypes represent a different morphotype and belong to a species different to M. leda . The 5 males comprise two different morphotypes, one of which is presumably conspecific with the workers of M. leda , but there is no way at this stage of correctly associating them.

Chelaner rothsteini leda (Forel) ; Ettershank, 1966: 97.

Monomorium rothsteini leda Forel ; Bolton, 1987: 300–301.

Monomorium rothsteini Forel ; synonymy by Heterick, 2001: 408.

Diagnosis. A medium sized amber orange species with small eyes and a deeply concave anterodorsal margin of the clypeus. The mesosoma is without dorsal sculpture except posteriorly and in the extreme lateral areas. T1 is smooth and the dorsal surface of the propodeum lacks longitudinal and transverse strigae.

Worker measurements (n=9). HW 0.82–0.90, HL 0.86–0.96, EL 0.14–0.17, PMH 0.33–0.47, PH 0.27–0.31, PNH 0.20–0.23, LHW 0.53–0.59, EW 0.10–0.12, PML 0.47–0.64, ML 0.86–1.05, PL 0.41–0.47, PNWdv 0.23–0.30.

Worker Description. Medium sized species with a medium sized, rectangular head; posterior cephalic margin mildly depressed in the centre. Anterodorsal margin of the clypeus deeply concave with angular frontolateral carinae extending beyond anteroventral clypeal margin forming obtuse angles; anteroventral margin with a small median projection. Frons strigae restricted to antennal lobes and area in between or limited to a few strigae only on antennal lobes; coarse lateral cephalic strigae not reaching eye margin in a majority of specimens, a few very fine strigae may reach eye margin. Eyes small, EW <0.20 x LHW, 12 ommatidia in longest vertical axis, 9 in longest horizontal axis.

Mesonotum mostly smooth with coarse strigae extending from metanotal groove onto lateral portions of posterior mesonotum only, rugulose between strigae, shallowly alveolate to rugose on lateral curvature posteriad of promesonotal suture line; posterior mesonotum centrally smooth and flat, contiguous with surrounding surface of mesonotum in a majority of specimens, some specimens with the posterior mesonotum slightly raised. Mesopleuron alveolate, a few strigae on dorsal half. Propodeum in lateral view with dorsolateral angles clearly forming an obtuse angle; laterally alveolate with strigae over the metapleural gland bulla extending to metapleural groove; dorsal surface with anterodorsal transverse carina absent in a majority of specimens, very weakly present in a few specimens, transverse and longitudinal strigae absent. Petiole node of medium breadth, between 2 and 2.5 x eye width when viewed from above; shape in posterior view oval; in lateral view anterior and posterior faces converging, apex rounded from higher anterior face to lower posterior face. Posterior surface of petiole node finely reticulate laterally only; postpetiole faintly reticulate laterally and along posterior basal margin. T1 completely smooth and without sculpture.

Head, mesosoma and legs amber orange to orange brown, petiole and postpetiole dorsally infuscated, metasomal tergites light to dark brown.

Distribution. This species is known only from the type locality which is the Kimberley region of northern Western Australia. The exact locality is unknown and a marker has been placed on the distribution map ( Fig. 11 d) only to indicate the general area where this species is found.

Remarks. Of all of the species removed from synonymy with M. rothsteini this is the only one for which there was no molecular data included in the molecular analysis of Sparks et al. (2013). However, the morphology of the worker lectotype and paralectotypes from the Kimberley district listed above separate this taxon from all others revised here.

As indicated above the concept of M. leda adopted here is based on the workers from the Kimberley district and those from Alice River, Queensland clearly belong to a different, as yet undescribed species. It is not possible to determine from Forel’s original description which population was used for the species concept and we have therefore chosen the population with the majority of type material. A further complication has emerged from Forel’s original syntype series in that two morphotypes are represented by the five male specimens from the Kimberley district, clearly representing two distinct species, neither of which can be associated with the worker caste as this time.

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.

FIGURE 11. Geographic distributions of species in the M. rothsteini (Forel) complex: (a): • bogischi, ⋅ broschorum, ˔ capeyork, + hertogi; (b): • eremum, ˔ eremoides + eremum and eremoides; (c): • geminum, ˔ topend, + geminum and topend; (d): • humilior, ⋅ kidmani, ˔ leda, + maryannae; (e): • merepah, ⋅ mitchell, ˔ oodnadatta, + pilbara; (f): • rothsteini, ⋅ speculum, ˔ stagnum, + hoffmanni.