Taxonomy and distribution of the genus Trichomyrmex Mayr, 1865 (Hymenoptera: Formicidae) in the Arabian Peninsula, with the description of two new species

The ant genus Trichomyrmex Mayr, 1865 is revised for the Arabian Peninsula based on the worker caste. Nine species are recognized and descriptions of two new species, T. almosayari sp. nov. and T. shakeri sp. nov. from Riyadh Province, Saudi Arabia, are given. For nomenclatural stability, lectotypes for T. abyssinicus (Forel, 1894a), T. lameerei (Forel, 1902) and T. mayri (Forel, 1902) are designated. A key to species and diagnostic characters of the treated species are presented. New country records are presented for T. abyssinicus (Saudi Arabia), T. destructor (Jerdon, 1851) (Saudi Arabia and the United Arab Emirates) and T. mayri (Qatar). New distributional records for T. destructor and T. mayri for Saudi Arabia are also provided. World and regional species distributions are indicated and distributional maps for nine Arabian species are included. Ecological and biological information is given when known.

The genus Trichomyrmex was established by Mayr (1865) for the type species T. rogeri Mayr, 1865 by monotypy, but later the genus was treated as a junior synonym of Monomorium (Mayr, 1855) (Ettershank 1966;Bolton 1987). This synonymy was accepted for nearly three decades until the milestone work of Ward et al. (2015) on the phylogeny of the Myrmicinae. In this study, Trichomyrmex was again recognized as a valid genus in the tribe Crematogastrini Forel, 1893, and included the former Monomorium scabriceps (Mayr, 1879) and destructor species groups.
Workers of Trichomyrmex can be recognized by the following characters: usually polymorphic; antennae 12-segmented, either lacking an apical club or with a club of 3 or 4 segments (usually 3, e.g., species of the destructor-group); masticatory margin of mandibles armed with 3-4 teeth, when 4 the basalmost tooth is reduced to an offset denticle or blunt angle; palp formula 2,2; scrobes absent; median portion of clypeus is short and does not project anteromedially; the anterior clypeal margin is only feebly convex to concave; clypeus usually with a distinct unpaired seta located at the midpoint of the anterior margin; the antennal fossae are surrounded by fine and curved striolae; metanotal groove impressed; propodeum unarmed, with transversely sculptured dorsum; propodeal spiracle usually circular to subcircular (vertical ellipse or short slit in T. abyssinicus (Forel, 1894)); sting absent. Most species nest directly in the ground, or under stones, or in rotten wood, or sometimes in more specialized habitats such as termitaries. The described species are considered either granivorous (T. abyssinicus, T. chobauti (Emery, 1897) (Bingham 1903)), or are predators or scavengers (T. destructor (Jerdon, 1851), T. mayri (Forel, 1902) (Bolton 1987)).
The first survey of the ant fauna of Saudi Arabia (Collingwood 1985) recorded only T. destructor and T. mayri. A decade later Collingwood & Agosti (1996) reported on the ants of the entire Arabian Peninsula, recording T. chobauti from Saudi Arabia and the United Arab Emirates and T. destructor, T. mayri, and T. robustior (Forel, 1892) from Saudi Arabia, Oman and Yemen. A list of introduced species in the United Arab Emirates (Collingwood et al. 1997) included T. destructor. The faunal treatment of the Formicidae of the United Arab Emirates (Collingwood et al. 2011) added four new records for the country, T. abyssinicus, T. chobauti, T. lameerei (Forel, 1902), and T. perplexus (Radchenko, 1997). In addition, two species, T. mayri and T. destructor, are known from the Socotra Archipelago (Collingwood et al. 2004;Sharaf et al. in press).
In the present study ants of the genus Trichomyrmex of the Arabian Peninsula are revised based on the worker caste. Lectotypes are designated for T. abyssinicus, T. lameerei and T. mayri.

Sampling Procedures
The specimens were collected by pitfall traps, malaise traps, and handpicking during collection surveys across different regions of the Arabian Peninsula. Type material of the treated species deposited in different museums were examined and compared for any discrepancies.

Illustrations
Specimens were photographed by April Nobile, Estella Ortega, Michele Esposito, Shannon Hartman, Will Ericson and Zach Lieberman (CAS). Digital color images of lateral and dorsal views of the entire body and full-face views of the head of each species were made using a Leica DFC450 digital camera with a Leica Z16 APO microscope and LAS (v3.8) software. These images are also available online on AntWeb (www.AntWeb.org) and are accessible using the unique identifying specimen code. Ecological and distributional information for the species were based on field observations together with data compiled from the literature and some ant websites, including www.AntWeb.org and www.antwiki.org. From these two websites, information about treated species, including taxonomic history, references, distribution, habitats and biology, were used. The species names follow the online catalogue of ants of the world (Bolton 2014) available from www.AntCat.org, and www.antwiki.org. Distribution maps were made using DIVA-GIS (version 7.5.0.0).

Description
Workers of this species exhibit marked size variation in any nest series.  (Bolton 1987).

Large workers
HeAd. In full-face view with emarginated posterior margin and nearly parallel sides; posterior corners strongly rounded; mandibles blunted; scapes when laid back from their insertions fail to reach posterior margin of head. MesosoMA. Metanotal groove broad and distinctly impressed in profile; promesonotum strongly convex in profile; propodeal spiracle a vertical ellipse or slit; propodeal dorsum about twice as long as propodeal declivity in profile.
Petiole. Petiolar peduncle with a distinct anteroventral process that consists of a triangular lamella followed by a broad flange; petiolar spiracle situated at midline of petiolar peduncle.
sculPture. Cephalic surface smooth and shining except area in front of eyes, which is finely rugulose in profile; mandibles strongly longitudinally rugulose; promesonotal dorsum strongly longitudinally rugulose or with disorganized rugulae, to smooth; propodeal dorsum distinctly transversely rugulose; mesosomal sides strongly rugulose; petiole and postpetiole irregularly rugulose, gaster smooth and shining.
colour. Head, mesosoma, petiole and postpetiole reddish brown or dark brown, gaster darker than head and mesosoma, blackish brown or black; head with a dark median longitudinal line in full-face view.
HeAd. In full-face view with emarginated posterior margin and sides diverging anteriorly; anterior clypeal margin distinctly concave medially between two well developed teeth that are situated anteriorly in front of the antennal insertions; mandibles armed with three teeth; eyes small, situated in front of midline of head sides (EL 0.14-0.24 × HW), with eight ommatidia in longest row; antennal scapes distinctly short, when laid back from their insertions they fail to reach posterior margin of head.
MesosoMA. Promesonotum nearly flat in profile; propodeal spiracle a vertical ellipse or slit; propodeal dorsum about twice as long as propodeal declivity in profile.
Petiole. Petiolar peduncle with a distinct anteroventral process that consists of a triangular lamella followed by a broad flange; petiolar spiracle situated at midline of petiolar peduncle.
sculPture. Cephalic surface smooth and shining except for area in front of eyes, which is finely rugulose in profile; mandibles strongly longitudinally rugulose; propodeal dorsum weakly, irregularly, transversely rugulose; mesosomal sides faintly rugulose; gaster smooth and shining.
colour. Lighter than large workers, pale brown or yellowish brown, gaster dark brown.

Differential diagnosis
Trichomyrmex abyssinicus can be distinguished from other Arabian species except T. perplexus by the vertical ellipse or slit propodeal spiracle. This species is similar to T. perplexus but can be separated from it by the convex promesonotum outline, the distinctly longer propodeal dorsum, and the irregularly rugulose propodeum, petiole and postpetiole.

Ecological and biological notes
Shada Al A'la Mountain peak is an extension of the Hijaz Mountains to the west and is a natural protectorate in Al Bahah Province. The region has a substantial plant biodiversity and the most abundant plants are Olea europaea ssp. africana (Mill.) P. Green. (Oleaceae), Coffea arabica L. (Rubiaceae), Juniperus procera Hochst. ex Endlicher (Cupressaceae), and Acacia spp. (Fabaceae).

Distribution
This species was originally described from Ethiopia and has a broad distribution in the Afrotropical region, especially the Sahelian Zone. It has been recorded from Benin, Burkina Faso, Ghana, Nigeria, Sudan, Tanzania (Bolton 1987), Egypt (Gebel Elba) (Sharaf 2006), and United Arab Emirates (Collingwood et al. 2011).
The distribution of T. abyssinicus appears to be restricted to the southwestern mountains of Saudi Arabia, since several years of collecting efforts by the senior author did not retrieve material from any region in the country except the present record, the first record from Saudi Arabia.

Etymology
The patronym almosayari has been selected to honor the late Egyptian Islamic writer Dr. Mohammed Sayed Almosayar . HeAd. Head short, only slightly longer than broad (CI 93-96), with feebly convex sides and emarginated posterior margin; anterior clypeal margin lacking teeth of any description; masticatory margin of mandibles armed with three teeth; eyes relatively large, with 12 ommatidia in the longest row (EL 0.25-0.27 × HW), reniform with ventral margin weakly but distinctly concave, dorsal margin distinctly broadly convex; scapes short, when laid back from their insertions failing to reach posterior margin of head (SI 74-90).
Pilosity. Underside of head with crowded, long J-shaped ammochaete hairs forming a psammophore; two pairs of hairs on pronotum and mesonotum, propodeum bare, petiole and postpetiole each with one pair of long hairs, gaster with decumbent pubescence; cephalic pilosity shorter than body pilosity.
sculPture. Mandibles longitudinally striolate; cephalic dorsum smooth and shining, except for scattered hair pits; area in front of eyes and behind posterior clypeal margin finely striolate; pronotal dorsum faintly shagreenate; mesosomal dorsum, sides, petiole and postpetiole finely and densely punctulate or shagreenate, general appearance dull; gaster smooth and polished.
color. Dark brown to blackish brown; mandibles, antennae, and legs brownish.

Differential diagnosis
Trichomyrmex almosayari sp. nov. can be immediately separated from all known African and Arabian species of the genus by the reniform eyes, the ventral eye margin feebly concave and the dorsal eye margin distinctly broadly convex.

Ecological and biological notes
The new species was foraging on dry sandy soil (Fig. 6D) surrounding shrubs of Rhazya stricta Decnet (Apocynaceae) and coexisting with several other ant species, including Camponotus sericeus (Fabricius, 1798), Cataglyphis semitonsa (Santschi, 1929), Messor ebeninus (Santschi, 1927), M. minor (André, 1883), Monomorium venustum (Smith, 1858), M. abeillei (Emery, 1881), and T. mayri. Several additional attempts to collect more material at the type locality were not successful, indicating that the new species may be an uncommon taxon. The type locality, Rawdhat Khorim, is one of the most important natural protectorates in Saudi Arabia due to its diverse flora (Al-Farraj et al. 1997, Alfarhan 2001. The region occupies an area of 24 km 2 , located about 95 km northeast of Riyadh (25.38˚ N, 47.28˚ E, alt. 560 m) (Vesey-Fizberald 1957). The diversity of the flora in Rawdhat Khorim is relatively high, with about 153 plant species in 32 families recognized (Alfarhan 2001 HeAd. As long as broad, with feebly concave posterior margin and weakly convex sides; anterior clypeal margin distinctly concave; eyes of moderate size (EL 0.18 × HW) with 11 ommatidia in longest row; scapes when laid back from their insertions reach posterior margin of head.
MesosoMA. Promesonotum convex in profile, running back to straight mesonotum; metanotal groove impressed; propodeal dorsum nearly twice as long as declivity in profile; propodeal spiracle circular, situated above midline of propodeum in profile.
PostPetiole. Node low and broad in profile.
Pilosity. Underside of head with long ammochaete J-shaped hairs forming a distinct psammophore; cephalic dorsum with sparse suberect hairs directed inward to midline of head; antennae with dense appressed pubescence; anterior clypeal margin with abundant long curved hairs; pilosity on mesosoma restricted to two or three pairs of hairs on pronotum and promesonotum; sparse decumbent pubescence on mesonotal and propodeal dorsum; petiole and postpetiole bare; gastral tergites with sparse appressed pubescence, few longer pairs of hairs present at gastral apex. sculPture. Clypeus, mandibles, and cephalic surface between frontal carinae and in front of eyes longitudinally rugulose; promesonotum and mesonotum faintly longitudinally rugulose; propodeum and sides of mesonotum, petiole and postpetiole densely punctulate-reticulate, gaster smooth and shining.

Differential diagnosis
Trichomyrmex chobauti is closest to almosayari sp. nov. and lameerei. All three species share the abundant long ammochaete J-shaped hairs that form a distinct psammophore on the underside of the head. Trichomyrmex chobauti can be readily separated from T. almosayari sp. nov. by the bicoloured body, the oval eyes, and the straight or feebly concave posterior margin of the head. From T. lameerei it can be distinguished by the smaller size, the longer antennal scapes that reach the posterior margin of the head, and the unsculptured posterior half of the head.

Distribution
Trichomyrmex chobauti was originally described from Algeria and recorded from the Middle East and from two countries of the Arabian Peninsula, Saudi Arabia and United Arab Emirates (Collingwood & Agosti 1996;Collingwood et al. 2011).
Trichomyrmex destructor (Jerdon,   Workers of this species exhibit size variation in any nest series.

Worker
HeAd. Mandibles with three strong teeth, the fourth (basal) reduced to a minute offset denticle; eyes relatively small (EL 0.14-0.20 × HW), with 4-6 ommatidia in longest row; in small workers scapes relatively long (SI 88-111), when laid back from their insertions reaching posterior margin of head; in large workers scapes relatively shorter (SI 70-104), failing to reach posterior margin of head.
PostPetiole. Postpetiolar node lower than petiolar node in profile.
Pilosity. Posterior margin of head with 2-4 pairs of hairs; cephalic surface behind frontal lobes with 1-4 pairs of hairs straddling midline; cephalic pubescence scattered and directed inward to midline; promesonotal dorsum and propodeum with many pairs of long hairs; petiole, postpetiole and gaster with backward directed long hairs.
sculPture. Cephalic surface smooth and shining, except areas in front of eyes and posterior margin of head (in dorsal view) finely striolate; mandibles longitudinally striolate; promesonotum and mesonotum smooth and shining; mesopleura densely punctulate-reticulate; propodeal dorsum finely transversely striolate to rugulose, fainter in smaller than in larger workers; gastral tergite smooth and shining.
colour. Head, mesosoma, petiole and postpetiole ranging from pale yellow to dull brownish yellow; gaster dark brown to blackish brown, with a distinct yellowish area mediobasally.

Differential diagnosis
The most similar species to T. destructor is T. mayri, from which it can be distinguished only by the bicoloured body. Head, mesosoma, petiole and postpetiole yellow to brown yellow, gaster dark brown, whereas T. mayri is unicolorous dark brown or black brown.

Ecological and biological notes
Workers of this species were foraging close to the trunk base of an Acacia sp. tree where the surrounding area was impacted by trash and human waste. Another nest series was found in moist soil under a stone next to a date palm, Phoenix dactylifera L. (Arecaceae). A nest series was also found under rooster tree, Calotropis procera (Aiton) W.T. Aiton (Asclepiadaceae) and associated with the ant species, T. mayri, Carebara arabica (Collingwood & Van Harten, 2001), Tapinoma melanocephalum (Fabricius, 1793), Nylanderia jaegerskioeldi (Mayr, 1904), Monomorium sp. and Cardiocondyla sp.

Distribution
Originally described from India, this species is now widely distributed in tropical and subtropical regions (Wetterer 2009). It has supposedly been dispersed by commerce from central Asia west to North Africa (Forel 1909;Sharaf 2006), southern Europe (Ruzsky 1907), the Arabian Peninsula (Collingwood 1985;Collingwood & Agosti 1996), and the Socotra Archipelago (Collingwood et al. 2004, Sharaf et al. in press).
HeAd. Broader than long, with emarginated posterior margin, rounded corners and feebly convex sides; anterior clypeal margin feebly concave; eyes of moderate size (EL 0.15-0.16 × HW) with 12 ommatidia in longest row; scapes when laid back from their insertions fail to reach posterior margin of head.
Petiole. Peduncle long; two small lateral projections at junction between node and peduncle seen in dorsal view; petiolar node high and rounded in profile.
Pilosity. Underside of head with abundant long J-shaped hairs forming a distinct psammophore; cephalic surface with sparse short hairs directed inward to midline of head; anterior clypeal margin with abundant long hairs; scapes with sparse appressed pubescence; funiculus with dense appressed pubescence; mesosoma with abundant short hairs, few longer pairs on pronotum and mesonotum; petiole with abundant short hairs; postpetiole with about seven pairs of long hairs directed backward; gaster with few sparse long hairs and abundant appressed pubescence.

Differential diagnosis
Separation is given under T. chobauti.

Ecological and biological notes
One paralectotype specimen is mounted with a seed between mandibles which indicates a granivorous feeding habitat of this species.

Distribution
This species was described from Algeria and recently recorded from United Arab Emirates (Collingwood et al. 2011).

Differential diagnosis
Separation is given under T. destructor.

Ecological and biological notes
A nest series was found under a Calotropis procera (Aiton) W.T.Aiton 1811 tree and coexisting with several ant species including: Carebara arabica (Collingwood & Van Harten, 2001), T. melanocephalum (Fabricius, 1793), N. jaegerskioeldi (Mayr, 1904), Monomorium sp. and Cardiocondyla sp. Another nest series was found under a stone next to a Citrus limon (L.) Burm. F. (Rutaceae) tree and a nest of Brachyponera sennaarensis (Mayr, 1862). Many workers were foraging on moist clay soil under a mango tree, Mangifera indica L. (Anacardiaceae). Some other workers were collected from dry leaf litter under a Myoporum insulare R.Br. (Scrophulariaceae) tree. A nest was found under a stone in moist soil and next to a Juniperus procera Hochst. ex. Endlicher (Cupressaceae) in the Asir Mountains. Some workers were foraging in leaf litter under a Psidium guajava L. (Myrtaceae) tree. Another nest was found in moist soil, rich in decayed organic matter and the surrounding area of dense grasses. Many workers were collected by sifting the leaf litter under date palms. In Shada Al A'la, a nest was found under a discarded bag filled with soil rich in decaying organic matter under a coffee tree, Coffea arabica L. (Rubiaceae). Several workers were found under the bark of Acacia sp. trees. A nest series was foraging under a pomegranate tree, Punica granatum L. (Lythraceae). Some workers were collected under a ficus tree (Moraceae) where soil was moist and rich in decaying organic matter.

Distribution
This species has successfully invaded many regions of the tropics, with a speculated origin in the Indian subcontinent (Bolton 1987). Geographically, this species has spread westward to the Middle East, the Arabian Peninsula (Collingwood 1985;Collingwood & Agosti 1996;, North Africa (Egypt) (Sharaf 2006) and along the coastal zones of Sub-Saharan Africa (Bolton 1987). Trichomyrmex mayri is the most successful and widely distributed species of the genus in the Arabian Peninsula and one of the most abundant ants of the Socotra Archipelago (Collingwood 2004;Sharaf et al. in press).
HeAd. Slightly longer than broad (CI 98-109) with concave posterior margin and convex sides; anterior clypeal margin shallowly concave; scapes short, when laid back from their insertions failing to reach posterior margin of head.
MesosoMA. Convex in profile; promesonotal outline flat; metanotal groove impressed; propodeum angular in profile or with short blunt rounded denticle; propodeal dorsum as long as declivity in profile; propodeal declivity with feeble longitudinal impression.
Petiole. Peduncle long; petiolar node low, triangular and rounded in profile.

PostPetiole. Node low and rounded in profile.
Pilosity. Underside of head with numerous straight short hairs not forming a psammophore; cephalic surface with abundant subdecumbent pubescence; posterior margin of head with numerous long curved hairs; mesosoma, petiole and postpetiole with many projecting hairs, varying in length; gastral pilosity numerous and sparse.
colour. Head, mesosoma, petiole and postpetiole orange red to reddish brown, gaster dark brown, legs brownish or reddish yellow.

Differential diagnosis
Separation is given under T. abyssinicus. In addition, T. perplexus seems similar to a species described under Monomorium, M. dentigerum (Roger, 1862), from Syria, but more material of both species is required in order to verify the synonymy.

Distribution
Trichomyrmex perplexus was described from Armenia and recorded from United Arab Emirates (Collingwood et al. 2011), the Middle East including Jordan, and Syria (Borowiec 2014), Eastern Europe and from the Mediterranean Basin including Greece, Turkey, and Cyprus (Borowiec 2014). It is common in the Aegean Islands, Crete, Macedonia, Dodecanese Islands, Ionian Islands, and Thessaly (Borowiec & Salata 2012L. Borowiec pers. comm.).
HeAd. With feebly convex sides and slightly concave or emarginated posterior margin in full-face view; in some individuals head broader anteriorly than posteriorly; anterior clypeal margin nearly straight or shallowly concave; basal mandibular tooth reduced to minute denticle; eyes of moderate size (EL 0.18-0.20 × HW), situated just in front of midline of head and with 6-8 ommatidia in longest row; scapes when laid back from their insertions just reach posterior margin of head.
MesosoMA. Promesonotum domed in profile; metanotal groove impressed; propodeal dorsum on a lower level than that of promesonotum in profile.
PostPetiole. Node at a much lower level than that of petiole in profile.
Pilosity. Underside of head with few short straight hairs, not forming a psammophore; cephalic surface with long fine decumbent to appressed pubescence directed toward midline of head; mesosomal dorsum with long erect to suberect hairs and abundant appressed pubescence; petiole, postpetiole, first gastral tergite and sternite with numerous long curved backward directed hairs and with sparse appressed pubescence. sculPture. Mandibles longitudinally rugulose, cephalic dorsum and sides of promesonotum smooth and shining; metapleuron and propodeal sides regularly punctulate-reticulate; propodeal dorsum finely transversely rugulose; petiole, postpetiole and gastral tergites entirely smooth and shining.
colour. Dark brown or blackish brown; gaster usually darker than head and mesosoma.

Differential diagnosis
The most similar species to T. robustior is T. mayri from which it can be separated by the smooth posterior margin of the head, the strongly convex promesonotal outline, the coarse and broadly spaced propodeal sculpture, and the longer and strongly curved body pilosity.

Distribution
This species was described from Somalia and recorded from Kenya and Madagascar (Bolton 1987). Trichomyrmex robustior has been recorded from Saudi Arabia, Oman and Yemen (Collingwood & Agosti 1996).

Etymology
The new species has been named in honor of the late Egyptian writer Mahmoud M. Shaker .

Material examined
Holotype SAUDI ARABIA: worker, Riyadh, Wadi Hanifa,24 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.
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.
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. 13D). Other sampling methods (soil sifting, light traps, beating sheets) were not successful in adding more material.

Distribution of Arabian Trichomyrmex species.
Geographic distributions of the Trichomyrmex species in the Arabian Peninsula are shown in Figs 14-17.

Discussion
Among the nine species of the genus Trichomyrmex reported from the Arabian Peninsula, T. mayri and T. destructor are the most abundant ones. However, T. mayri is the most successfully distributed species, since it has the ability to establish itself in a broad range of habitats, including desert and agricultural, wild and urban, pristine and disturbed sites (Collingwood 1985;Collingwood & Agosti 1996;Collingwood et al. 1997Collingwood et al. , 2011. These observations agree with Collingwood et al. (2004) and Sharaf et al. (in press) on Socotra, where T. mayri has a broad distributional range on the Archipelago, occurring in different habitats. The species is also recorded from different localities in Egypt, including the Sinai and Nile Delta (Sharaf 2006). The two species are recorded here for the first time from Qatar, which is not surprising, especially under the intensive urbanization that has occurred recently (UNCSD 2004).
Trichomyrmex mayri is most similar to T. destructor in all morphological characters except the colour, which is uniform dark brown in the former and yellow to brown yellow with a dark brown gaster in the latter. Although the separation of species based on colour is a feeble character, especially for genera that having distinct colour variation, like Trichomyrmex and Monomorium, it is observed that the colour is consistent for the studied material of both species in the Arabian Peninsula; therefore, we treat both as valid species. However, it is likely that a future probability for synonymizing mayri and destructor exists especially when using molecular techniques. Trichomyrmex abyssinicus is reported here for the first time from Saudi Arabia. The newly described species T. almosayari sp. nov. and T. shakeri sp. nov. appear to be restricted to Riyadh Province (Central region). Relatively few specimens of the three species have been collected despite intensive efforts using a variety of sampling methods. All specimens were collected using pitfall traps.  (Forel, 1894a), T. almosayari sp. nov., T. chobauti (Emery, 1897), T. lameerei (Forel, 1902) and T. shakeri sp. nov.   (Forel, 1902).  (Radchenko, 1997) and T. robustior (Forel, 1892). 246: 1-36 (2016)