Trichomyrmex shakeri Sharaf & Al Dhafer

Mostafa R. Sharaf, Shehzad Salman, Hathal M. Al Dhafer, Shahid A. Akbar, Mahmoud S. Abdel-Dayem & Abdulrahman S. Aldawood, 2016, Taxonomy and distribution of the genus Trichomyrmex Mayr, 1865 (Hymenoptera: Formicidae) in the Arabian Peninsula, with the description of two new species, European Journal of Taxonomy 246, pp. 1-36 : 28-31

Trichomyrmex shakeri Sharaf & Al Dhafer sp. nov.

urn:lsid:zoobank.org:act:CBBBD8CB-46EF-4D9E-9BBC-4252822A9206

Fig. 13 A–C

Etymology

The new species has been named in honor of the late Egyptian writer Mahmoud M. Shaker (1909–1997).

Material examined

Holotype

SAUDI ARABIA: worker, Riyadh, Wadi Hanifa, 24.90˚ N, 46.18˚ E, alt. 814 m, 12 Oct. 2015, Aldhafer et al. leg. ( KSMA).

Paratypes

SAUDI ARABIA: 1 w, same data as the holotype (KSMA); 4 w, Riyadh, Wadi Hanifa, 24.90˚ N, 46.18˚ E, alt. 806 m, 29 Apr. 2015, Aldhafer et al. leg. (1 in CASC: CASENT0922068; 3 in KSMA). Type material is collected by pitfall traps.

Description

MEASUREMENTS. Holotype, worker. TL 2.07; HL 0.62; HW 0.56; SL 0.48; EL 0.19; ML 0.56; PW 0.31; PTL 0.14; PTW 0.09; PPL 0.08; PPW 0.15; CI 90; EI 34; SI 86.

WORKER. TL 1.94–2.33; HL 0.58–0.67; HW 0.52–0.64; SL 0.36–0.48; EL 0.18–0.21; ML 0.53–0.66; PW 0.29–0.34; PTL 0.14–0.18; PTW 0.09–0.13; PPL 0.08–0.15; PPW 0.14–0.18; CI 85–96; EI 31–37;

SI 68–86 (n = 5).

HEAD. Slightly longer than broad and broader anteriorly than posteriorly, with emarginated posterior margin and feebly convex sides; anterior clypeal margin nearly straight or feebly convex; eyes large (EL 0.31–0.36 × HW), with 11 ommatidia in longest row; scapes when laid back from their insertions surpassing posterior margin of head by about one third of eye length.

MESOSOMA. Promesonotum distinctly convex in profile; metanotal groove impressed.

PILOSITY. Underside of head with few short straight hairs, not forming a psammophore; cephalic surface and mandibles with sparse short hairs, anterior clypeal margin with a median long hair and two pairs of long hairs on each side; antennae with dense appressed pubescence; mesosoma without hairs except for few sparse appressed pubescence on promesonotum.

PETIOLE. With one pair of long, backward directed hairs.

POSTPETIOLE. With two pairs; first gastral tergite bare except for few sparse appressed pubescence, the remaining gastral tergites with some long hairs.

SCULPTURE. Cephalic surface smooth and shining except posterior margin of head, area in front of eyes and mandibles longitudinally rugulose; promesonotal dorsum faintly irregularly sculptured; mesopleura, propodeum, petiole and postpetiole densely punctulate-reticulate; gaster smooth and shining.

COLOUR. Uniform yellow, eyes black, mandibular teeth dark brown.

Differential diagnosis

Among the Arabian Trichomyrmex species, T. shakeri sp. nov. is a conspicuous species, quickly identified by the uniform yellow colour and the exceptionally larger eyes (EL 0.31–0.36 × HW) compared to other sympatric species. Trichomyrmex shakeri sp. nov. is superficially similar to T. santschii (Forel, 1907) from North Africa (Tunisia) in colour and measurements, but it can be readily separated by the absence of the psammophore, which is well-developed in T. santschii .

Ecological and biological notes

This species is considered uncommon. Only six workers were collected in 150 pitfall traps run for one year at the type locality, a relatively pristine section of Wadi Hanifa ( Fig. 13 D). Other sampling methods (soil sifting, light traps, beating sheets) were not successful in adding more material.

Figures

Fig. 13. Trichomyrmex shakeri sp. nov., paratype, worker (CASENT 0922068). A. Body in profile. B. Body in dorsal view. C. Head in full-face view (photos: Michele Esposito). D. Type locality (photo: A. Shams Alola).