Nesomyrmex zaheri Sharaf, Akbar & Hita Garcia

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 : 28-29

Nesomyrmex zaheri Sharaf, Akbar & Hita Garcia sp. n. Figs 3B, 6

Type material.

Holotype, pinned worker, YEMEN: Al Kawd, 13.088622° N, 45.364722° E, light-trap, 6770, 07.IX.2001, (A. van Harten) (WMLC: CASENT0906379).

Diagnosis.

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

Description.

Holotype worker measurements. HL 0.71; HW 0.55; SL 0.49; EL 0.17; PH 0.30; PW 0.42; WL 0.83; PSL 0.07; PTL 0.17; PTH 0.21; PTW 0.18; PPL 0.12; PPH 0.21; PPW 0.24; OI 31; SI 89; CI 77; DMI 51; LMI 36; PSLI 10; LPeI 81; DPeI 106; LPpI 57; DPpI 200; PPI 133.

Head. Masticatory margin of mandible with four teeth, decreasing in size from largest, acute apical tooth to smallest basal denticle; clypeus smoothly arched-convex and without a small median triangular projection; head in full-face view appearing almost rectangular, longer than broad (CI 77), sides of head almost straight, broader posteriorly behind eye level and narrowest directly behind posterior eye margin; posterior head margin slightly concave medially; frontal carinae and antennal scrobes absent; antennal scapes short, not reaching posterior head margin (SI 89). Eyes of moderate size (OI 31), with eight to nine ommatidia in the longest row.

Mesosoma. In lateral view mesosomal outline relatively low (LMI 36) and flat without any metanotal groove; promesonotal suture present laterally and completely absent dorsally; pronotum marginate between lateral and dorsal mesosoma, anterodorsal corners slightly denticulate; propodeum armed with short propodeal teeth (PSLI 10); propodeal lobes moderately developed and rounded.

Waist segments and gaster. Petiolar peduncle moderate short; in profile petiolar node relatively high and narrowing from base to apex, around 1.2 times as high as long (LPeI 81); anterior and petiolar faces truncate; node in dorsal view weakly wider than long (DPeI 106) and denticulate; in profile postpetiole globular, about 1.8 times as high as long (LPpI 57); in dorsal view about twice as wide as long (DPpI 200); postpetiole in dorsal view around 1.3 times as wide as petiolar node (PPI 133).

Sculpture. Mandibles shagreened with prominent but weak, irregular, longitudinal rugulae; median clypeal carina absent, two lateral, longitudinal, rugae on each side; cephalic dorsum posteriorly and laterally weekly reticulate-rugose, medially mostly with conspicuously reticulate-punctulate ground sculpture; mesosoma laterally and dorsally with distinct reticulate-punctulate ground sculpture, lateral mesosoma also with few conspicuously longitudinal rugae; dorsum reticulate-rugose with some irregular, longitudinal elements medially; legs unsculptured, smooth and shining; petiole and postpetiole with prominent reticulate-rugose sculpture superimposed on reticulate-punctulate ground sculpture; gastral tergites mostly smooth and shiny.

Pilosity and pubescence. Head, mesosoma, waist segments and gaster dorsally with stout, erect, blunt, and moderately short pilosity; head laterally and ventrally with short appressed to decumbent pubescence; pubescence on mesosoma and waist segments sparse to absent; gastral tergites with short appressed to decumbent pubescence.

Coloration. Body uniformly light brown with head darker and the appendages lighter in colouration.

Etymology.

The patronym zaheri has been selected to honor the late famous Egyptian Qura’an reader Sheikh Abdel-Azim Zaher (1904-1971).

Distribution.

At present the new species is only known from the type locality, which is located near the Indian Ocean in southwestern Yemen near Aden. Nothing is known about the biology or nesting behavior of the species.

Comments.

The new species is clearly a member of the N. angulatus species group sensu Hita Garcia et al. (2017). It is the third species known from the Arabian Peninsula and can be well separated from the other two species by the characters given in the key. Nesomyrmex zaheri can be easily distinguished from N. humerosus . However, N. zaheri and N. angulatus are morphologically very similar and differ only by a few morphological characters. As noted above, N. zaheri differs from N. angulatus by the lack of a median clypeal carina and a much shorter third mandibular tooth. In addition, N. zaheri has a slightly wider (DPpI 200 vs. 154-188) and higher (LPpI 57 vs. 68-91) postpetiole. These measurements may be found to overlap if additional specimens of N. zaheri become available. It is possible that the holotype of N. zaheri may be a geographical variant of the widespread N. angulatus . However, we examined several hundred N. angulatus from throughout its recognized geographical distribution and all specimens possessed a median clypeal carina, a character, which is usually stable in ants.