Tapinoma wilsoni

The specimens of T. wilsoni were found foraging on the ground, and coexisting with the ant species Carebara abuhurayri Sharaf & Aldawood, Tetramorium sericeiventre Emery, Pheidole minuscula Bernard, Pheidole sp., Trichomyrmex destructor (Jerdon), Monomorium exiguum (Forel), Monomorium sp., and Crematogaster sp. The type locality of this new species is a semi isolated area which is completely surrounded by high mountains and largely under banana cultivation. The new species was collected at the base of banana trees. Due to continuous irrigation of the banana plantations, the soil is moist throughout the year. The type locality still has a diversity of native plants as well as many other cultivated species, especially date palm, Ficus trees, alfalfa and some lemon trees. Numerous small streams drain this area.

Tapinoma wilsoni is the first new species to be described in the genus since Collingwood’s (1985) review of the Arabian ant fauna. We believe that the Mountains of Al Sarwat and Asir (southwestern region of the Arabian Peninsula) may yield a wealth of undescribed ant species.

Identification
Sharaf1 et al. (2012) - Tapinoma wilsoni appears most similar to Tapinoma lugubre, which was described from Zimbabwe. The two species are similar in size (TL 1.50–1.80) and both have the propodeum in profile with the transition from dorsum to declivity sharply defined, the declivity concave, and the angle with a raised apex. Tapinoma wilsoni can be easily separated from T. lugubre by the following characters: color brownish yellow or yellowish with fine brownish tint on head dorsum, appendages clear yellow, while T. lugubre is much darker brown or dull yellowish black, with occiput and gaster blackish. In T. wilsoni, the scape surpasses the posterior margin of head by about 1/6 of its length, whereas in T. lugubre, the scape surpasses the posterior margin of head by about 1/4 not similar in formatting to 1/6 in the above line!. In addition, T. wilsoni has the anterior clypeal margin distinctly concave, while in T. lugubre the middle of the anterior clypeal margin is shallowly concave. Moreover, T. wilsoni has two pairs of setae on the dorsum of the head, one close to antennal insertions and the other at the level of the anterior margin of eyes and several pairs on clypeus; whereas T. lugubre lacks hairs on the dorsum of the head. T. wilsoni can be easily separated from other Arabian species by the concave propodeal declivity and the well-defined angle between dorsum of propodeum and declivity.

Bharti, Kumar1 and Dubovikoff (2013) - Key to lugubre species-group workers:

1


 * Anteromedial clypeal margin with a wide shallow medial concavity . . . . . Tapinoma lugubre
 * Anteromedial clypeal margin more deeply concave 2

2


 * Head relatively wide and short (CI 0.82). Scape is relatively short, surpassing of posterior margin of head about on 1/4 of its length (SI 0.88) . . . . . Tapinoma wilsoni
 * Head more narrow and long (CI 0.8). Scape is very long, surpassing of posterior margin of head more than 1/3 of its length (SI 1.2). . . . . Tapinoma himalaicum

Distribution based on Regional Taxon Lists
Afrotropical Region: Saudi Arabia.

Nomenclature

 *  wilsoni. Tapinoma wilsoni Sharaf & Aldawood, in Sharaf, Aldawood & El Hawagry, 2012: 38, figs. 1-3 (w.) SAUDI ARABIA.

Worker
Holotype: TL: 1.84, HL: 0.51, HW: 0.41, SL: 0.46, PW: 0.29, WL: 0.56, EL: 0.11. Indices: CI: 80, SI: 112, OI: 27, EPI: 71, DTI: 134. Paratypes: TL: 1.56-1.84, HL: 0.49-0.53, HW: 0.36-0.42, SL: 0.35-0.51, PW: 0.25-0.31, WL: 0.49-0.63, EL: 0.09-0.14. Indices: CI: 73-84, SI: 105-133, OI: 22-33, EPI: 67-82, DTI: 114-145 (11 measured).

Head distinctly longer than broad with feebly convex posterior margin and sides; anterior clypeal margin broadly and distinctly concave; scapes, in full-face view, surpassing posterior margin of head by about 1/6 of its length; all funicular segments clearly longer than broad; eyes relatively large (OI 22-33) with 8 ommatidia in the longest row; mandibles large, armed with two distinct apical teeth followed by two smaller teeth, the third tooth being smaller than the fourth; the remaining masticatory margin equipped with several indistinct and tiny denticles; mandibles with several long yellow hairs; head pilosity a fine, whitish, appressed pubescence; promesonotum in profile straight or feebly convex; metanotal groove indistinct; propodeum in profile with the transition from dorsum to declivity sharply defined, the declivity concave and the angle with a raised apex; body pilosity restricted to two pairs of setae on dorsum of head, located close to antennal insertions and at the level of the anterior eye margin, none on mesosoma, one pair on second and third gastral tergites (absent in some individuals), apex of gaster with several pairs of long hairs; body very finely and densely shagreenate; mesosoma dull, head and gaster more or less shining. Color brownish yellow or yellowish with very faint brownish tint on dorsum of head, appendages clear yellow.

Type Material
Holotype worker. Saudi Arabia, Al Baha, Al Sarawat Mountains, Dhi Ayn Archaeological Village, 19.92972 N, 41.44278 E, 741 m, 15.v.2011 (M. R. Sharaf Leg.); deposited in the King Saud Museum of Arthropods, College of Food and Agriculture Sciences, King Saud University, Riyadh, Kingdom of Saudi Arabia. Paratype workers. 29 workers, same locality as holotype, deposited as follows: 1 in (Dr Bernhard Merz); 1 in  (Mrs. Isabelle Zürcher-Pfander); 1 in  (Dr Brian Fisher); 1 in  (Dr Stefan Cover); 2 in  (Tony Hunter), 1 in  (Mr. Barry Bolton); 1 in  (Prof. Michael S. Engel) the remaining specimens in  (M. R. Sharaf).