Nesomyrmex angulatus (Mayr, 1862)

Sharaf, Mostafa R., Akbar, Shahid Ali, Aldawood, Abdulrahman S. & Garcia, Francisco Hita, 2017, Review of the ant genus Nesomyrmex Wheeler, 1910 (Hymenoptera, Formicidae, Myrmicinae) from the Arabian Peninsula, African Invertebrates 58 (2), pp. 21-37 : 25-26

Nesomyrmex angulatus (Mayr, 1862) Figs 2C, D, 3A, 4

Leptothorax angulatus Mayr, 1862: 739 (w.). EGYPT. Santschi 1914: 107 (q.). [Combination in L. (Goniothorax) : Emery 1896: 58 (footnote); in Nesomyrmex : Bolton 2003: 272. See also: Mbanyana and Robertson 2008: 38. Current subspecies: nominal plus lybica].

Leptothorax angulatus r. ilgii Forel, 1894: 82 (w.). ETHIOPIA. Santschi 1912: 148 (q.). [Combination in L. (Goniothorax) : Wheeler W.M. 1922: 891. Junior synonym of N. angulatus : Bolton 1982: 324].

Leptothorax latinodis Mayr, 1895: 130 (w.). MOZAMBIQUE. [Combination in L. (Goniothorax) : Emery 1896: 58 (footnote). Junior synonym of N. angulatus : Bolton 1982: 324].

Leptothorax angulatus var. concolor Santschi, 1914: 107, fig. 15 (w.) KENYA. Emery 1915: 16 (q.m.). [Junior synonym of N. angulatus : Bolton 1982: 324].

Material examined.

KENYA: Coast Province, Malindi, Arabuko Sokoke Forest, -3.29, 39.98, 10-15 m, coastal hard wood forest, 24.V.2001 (R.R. Snelling) (FHGC: 3w); Coast Province, Malindi, Arabuko Sokoke Forest, -3.321, 39.929, 50 m, coastal dry forest, VI.2009 (F. Hita Garcia & G. Fischer) (FHGC: 3w); Rift Valley Province, Laikipia, Ewaso Ngiro, near Mpala Research Centre, 0.30, 36.91, 1600 m, Acacia woodland, 10.IV.2001 (R.R. Snelling) (FHGC: 10w); Rift Valley Province, Laikipia, Mpala Research Centre, 0.29, 36.9, 1650 m, Acacia woodland, 27.-28.IX.1999 and 24.III.2001 (R.R. Snelling) (FHGC: 3w); Western Province, Kakamega Forest, Buyangu Village, 0.3590, 34.8708, 1590 m, farmland, VII.2007 (F. Hita Garcia) (FHGC: 3w); MOZAMBIQUE: Sofala Province, Gorongosa National Park, Explore Gorongosa Park, -18.927, 34.378, 24 m, Fever tree forest, 20.V.2012 (G.D. Alpert) (MCZC: 3w); Sofala Province, Gorongosa National Park, 3 km W Chitengo, -18.992, 34.325, 37 m, riverine forest, 19.IV.2013 (G.D. Alpert) (MCZC: 3w); KINGDOM OF SAUDI ARABIA: Al Baha Province, Al Mukhwah, Dhi Ayn Archeological village, 19.929417°N, 41.441722°E, 741 m, 18.V.2010, (M. R. Sharaf) (KSMA: 3w); Elqamh park, Baljurshi, 19.913056°N, 41.905°E, alt. 1931 m, 17.V.2010, (M. R. Sharaf) (KSMA: 1w). Asir Province, Khamis Mushayt, W. Ben Hashbal, 18.594806°N, 42.650361°E, 1892 m, 26.IV.2011, (M. R. Sharaf) (KSMA: 6w); ZIMBABWE: Zebra Island, south side, -16.573, 28. 901, 12.V.2012 (J.K. Wetterer) (FHGC: 1w).

Diagnosis.

The following character combination distinguishes N. angulatus from the other members of the group in the Arabian Peninsula: third mandibular tooth relatively larger and better developed; anterior clypeal lobe always conspicuously developed, convex and rounded, never with a small median triangular projection; clypeus with median longitudinal carina; pronotum anterodorsally without sharp, dentate corners; in profile mesosomal dorsum forming a single, uninterrupted flat surface without any trace of metanotal groove; petiole with very well developed node.

Worker measurements

(n=19). HL 0.70-0.91; HW 0.55-0.71; SL 0.50-0.67; EL 0.17-0.22; PH 0.26-0.41; PW 0.37-0.57; WL 0.75-1.21; PSL 0.05-0.14; PTL 0.17-0.27; PTH 0.20-0.34; PTW 0.20-0.34; PPL 0.15-0.26; PPH 0.17-0.30; PPW 0.25 -0.40; OI 27-35; SI 88-97; CI 76-86; DMI 44-56; LMI 30-37; PSLI 6-16; LPeI 57-88; DPeI 114-137; LPpI 68-91; DPpI 154-188; PPI 111-160.

Distribution.

As already pointed out by Hita Garcia et al. (2017), this species has the widest distribution of any species of the N. angulatus group, and is certainly the most widespread Nesomyrmex species worldwide. Nesomyrmex angulatus has been reported from most African countries, as well as on the Arabian Peninsula and most of the Malagasy Region. The species seems to prefer comparatively arid environments and is predominantly found in cavities of dead wood, trunk of trees, lower vegetation and rarely on the ground ( Bolton 1982; Mbanyana and Robertson 2008).

Comments.

This species exhibits remarkable variability throughout its distributional range, most notably in the shape of the petiolar node ( Bolton 1982, Hita Garcia et al. 2017), but it is also relatively variable in body size and eye size. It is likely that the material currently understood to be N. angulatus is actually a complex of cryptic species. However, in order to examine this question in detail it would be necessary to gather substantial material from throughout its whole distribution range from numerous museum collections. Despite that this is a highly desirable undertaking; it is outside the scope of the current study that focuses on the Arabian fauna only.