Monomorium marjoriae DuBois 1986

Seifert, Bernhard, 2025, The Monomorium carbonarium species group in the Nearctic and Europe (Hymenoptera: Formicidae), Soil Organisms (Toronto, Ont.) 97 (1), pp. 55-84 : 76

Monomorium marjoriae DuBois 1986

[description, zoogeography]

The species has been described by a single nest sample from Mexico: Nayarit: Puga (DuBois wrote “Punga” – obviously a misspelling). These types were not available but this taxon shows exceptionally clear characters to allow an identification even by the rough description of DuBois (1986) .

All material examined. Numeric phenotypical data were taken in two samples with 8 workers from Tepic and Santiago Ixcuintla in Mexico. For details see supplementary information SI1, SI2 .

Geographic range. The three known sites in Mexico – Puga (21.58°N, 104.82°W, 700 m), Tepic (21.50°N, 104.89°W, 937 m) and Santiago Ixcuintla (21.81°N, 105.21°W, 17 m) – are situated in the Province Nayarit .

Diagnosis: --Worker ( Tab. 2, Figs. 13-15, key). Comparatively large, CS 504 ± 11 µm. Head moderately long, CL/CW 1.226 ± 0.024. Dents on clypeal margin short (ExCly/CS 2.53 ± 0.40%), not very acute and moderately distant (ClSpD/CS 9.31 ± 0.46%). Frontal carinae moderately approached (FR/CS 0.266 ± 0.009) and only weakly diverging frontad (FL/CS 0.274 ±0.010, FL/FR 1.033 ±0.024). Eye smaller and preocular distance larger than in other species (EL/CS 0.187 ± 0.004, PrOc/CS 0.252 ±0.004). Scape and funiculus segments much longer than in most other species (SL/CS 0.887 ± 0.006, Fu2/CS 6.67 ± 0.28%, Fu3/CS 5.53 ± 0.09%). Mesosoma more slen- der than in all other species (ML/CS 1.270 ± 0.013, MW/ CS 0.536 ± 0.006). Metanotal groove rather deep, MGr/ CS 5.41 ± 0.64%. Dorsal profile and posterior slope of propodeum straight and forming a distinct angle of 130° with a clear corner ( Fig. 14 ). Waist segments moderately high and wide (PeW/CS 0.280 ± 0.016, PeH/CS 0.372 ± 0.007, PpW/CS 0.329 ± 0.013, PpH/CS 0.290 ± 0.005). All body surfaces rather smooth, with exception of few rugulae on frontal lobes, ventrolateral area of meso- and metapleuron and genae. Lighter colored than other species: Head brown to dark brown, mesosoma yellowish-brown to brown, gaster brown to dark brown, mandibles yellowish-brown.

--Gyne: unknown

Taxonomic comments. Based on the characters underlined in the above description, the worker is comparably easy to determine and clearly separated as distinct cluster by explorative data analyses. The second and third component of a principal component analysis considering all 19 characters placed the M. marjoriae as well as those of M. monomorium and M. lorenzoi n.sp. widely separate from the samples of the seven remaining species of the M. carbonarium species complex ( Fig. 36 ).

Biology. Unknown.

Monomorium viridum Brown 1943

Figures

Figure 14. Lateral aspect of Monomorium marjoriae; Mexico: Santiago Ixcuintla, coll. T. Pergande

Figure 36. Sample means of principal component analysis considering 19 characters measured in workers. Monomorium monomorium – black dots, M. marjoriae – black squares, M. lorenzoi – black rhomb, M. ebeninum – white triangles, M. ergatogyna – black X, M. compressum – black triangle, M. gallicum n.sp. – white dots, M. carbonarium – white rhombs, M. viridum – black crosses, M. emarginatum – white squares.