Brachyponera sennaarensis

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Brachyponera sennaarensis
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Brachyponera
Species: B. sennaarensis
Binomial name
Brachyponera sennaarensis
(Mayr, 1862)

Pachycondyla sennaarensis sam-hym-c000111a profile 1.jpg

Pachycondyla sennaarensis sam-hym-c000111a dorsal 1.jpg

Specimen labels


Widely distributed throughout sub-Saharan Africa, where it inhabits savannas and open forests; it is also the most common member of the subfamily in southern Arabia. While it is regarded as native at least throughout Africa, it is also notably preferring man-impacted habitats, such as human settlements, rubbish dumps and waste ground. Thus it is in question whether the species is indigenous to the Socotra Archipelago. It is a general scavenger but will attack other insects and has a painful sting. Allergic reactions to the sting, sometimes severe, are a problem locally in Arabia (DIB 1992, RrzK et al. 1998), where it is called the "Samsun ant". Probably because of awareness of the painful sting, Socotri people refer to this ant by a specific denomination ("diftim"), as different to the word for ant ("nimihil"). (Collingwood et al. 2004)

Pashaei Rad et al. (2018) found this species in Iran in a very low rainfall area in a damp habitat in a house.

At a Glance • Facultatively polygynous  



Sharaf et al. (2017) - Worker. Large species (TL 5–6). Head broader than mesosoma, with convex sides and emarginated posterior margin; eyes relatively large; metanotal groove deeply impressed; petiole a high and thick node with a straight anterior surface and a convex posterior surface; first and second gastral tergites separated by a distinct constriction characteristic for ponerine ants; gaster ending with a powerful sting. Dark brown to blackish brown, antennae, tibiae and tarsi reddish. All body surfaces covered with fine and dense pubescence.

Keys including this Species


Distribution based on Regional Taxon Lists

Afrotropical Region: Burkina Faso, Cameroun, Chad, Eritrea, Guinea, Ivory Coast, Kenya, Mali, Namibia, Niger, Saudi Arabia, Senegal, Sierra Leone, Socotra Archipelago, Sudan (type locality), United Arab Emirates, Yemen, Zambia, Zimbabwe.
Oriental Region: India.
Palaearctic Region: Bahrain, Iran, Oman, Qatar.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


This appears to be the only ponerine ant that can feed on seeds. Diet varies seasonally and geographically: in humid tropical regions of Africa, both seeds and insect prey are collected during the rainy season, whereas diet consists exclusively of seeds during the rainy season that lasts three months (Dejean & Lachaud 1994). In dry tropical regions however, foragers react to the absence of seeds in the rainy season by adopting a 100% animal diet (Lévieux 1979).


Billen and Al-Khalifa (2015) - Abstract: The pro- and postpharyngeal glands of Brachyponera sennaarensis both appear as globular formations at a general anatomical level. However, only for the propharyngeal gland do these formations correspond with spherical secretory cells with diameters of 30-40 μm. For the lobed postpharyngeal gland, in contrast, this globular appearance is caused by the bulbous protrusions of the epithelial cells. This lobed appearance and globular cell shape also occur in the postpharyngeal glands of other Ponerinae and thus may represent a phylogenetic character. At the ultrastructural level, the propharyngeal gland cells are characterized by a well-developed granular endoplasmic reticulum, which is in agreement with its presumed production of digestive enzymes. The postpharyngeal gland cells contain a well-developed smooth endoplasmic reticulum, which allows the production of a nonproteinaceous secretion.

Billen and Al-Khalifa (2018) - As in other stinging ants, the venom gland of both queens and workers is formed by two free filaments in which the initial venom synthesis starts, a reservoir sac that encloses the convoluted gland portion, and the venom duct, that opens through the sting (Fig. 1). The paired filaments have a length of approx. 1.5-2 mm and a diameter between 40 and 50 μm, and are situated in between the other abdominal organs with a close proximity to the fat body (Fig. 2A). Both filaments fuse together to become a single unpaired filament shortly before entering the reservoir sac. The unpaired filament is considerably thinner than the paired filaments and has a diameter of 10-15 μm (Fig. 2B). Upon entering the reservoir sac, it expands to form the convoluted gland portion, which is entirely invaginated inside the reservoir sac (Fig. 2C, 4A). The reservoir sac is surrounded by a thick muscular supply (Fig. 2C), while also an occasional nerve can be observed (Fig. 2B). The elongated reservoir sac has a length of approx. 700 μm and a width around 400 μm, and has a cuticle-lined epithelial wall with a thickness of less than 1 μm (Fig. 2D). The venom duct has a length of approx. 750 μm and a diameter around 50 μm and enters the sting base dorsally to the Dufour gland duct, both ducts are associated with bundles of muscle fibres (Fig. 2E,F).

The venom gland filaments consist of class-3 secretory cells (classification of Noirot & Quennedey 1974) that are arranged around a central cuticle-lined filament lumen, into which they open through their accompanying duct cells (Fig. 3A). Each duct cell connects with a secretory cell through the end apparatus, which is formed by a cuticular continuation of the ductule that is surrounded by a sheath of microvilli (Fig. 3B). The cuticular characteristics in the duct cell and the end apparatus differ considerably: in the duct cell, the cuticular lining is thick and continuous, whereas in the end apparatus it is thin and discontinuous (Fig. 3B). The cytoplasm contains a well-developed Golgi apparatus and numerous mitochondria. Endoplasmic reticulum could not be observed, but numerous free ribosomes and polysomes give the cytoplasm a fine granulated appearance (Fig. 3C). In between the secretory cells of the free filaments, tracheoles (not shown) and nerve fibres can be observed (Fig. 3D).

The ovoid convoluted gland is completely internalized inside the reservoir sac, and measures approx. 400x200 μm. Careful tearing open of the reservoir sac of critical point dried material allows observation of the convoluted gland with scanning microscopy (Fig. 4A). Its external surface appears striated, with irregularly scattered small pores with a diameter around 0.5 μm (Fig. 4B). The internal reservoir wall, in contrast, shows a less dense striation without any pores (Fig. 4C). As a continuation of the venom gland filaments, the bulk of the convoluted gland is made up of secretory tissue with class-3 gland cells with a clear end apparatus and their accompanying ducts. The ducts open both along the continuation of the internal lumen inside the convoluted gland lumen and along the periphery of the convoluted gland (Fig. 1, 4D,E).

Photo Gallery

  • Billen and Al-Khalifa (2015) - Figure 1. Scanning electron micrographs of the pharyngeal glands of Brachyponera sennaarensis workers. A. Frontal view of the head with dissected pharyngeal glands (enlarged in B) shown at the same magnification. B. Ventral view of pharynx (ph) with attached pro-(ProPG) and postpharyngeal glands (PPG). C. Detail of secretory cells (SC) and slender duct cells (DC) of propharyngeal gland. Arrows indicate local widening of duct cells in region where duct cell nucleus occurs.
  • Billen and Al-Khalifa (2018) - Figure 1. Schematical representation of the sting (St) with its associated venom gland and Dufour’s gland (DG). CG: convoluted gland, VD: venom duct, VF: venom gland filaments, VGr: venom gland reservoir.
  • Billen and Al-Khalifa (2018) - Figure 2. A. Scanning micrograph of the sting apparatus with attached hindgut (HG) and Malpighian tubules (MT) of B. sennaarensis worker. The venom gland consists of two free filaments (VF), a reservoir (VGr) with an internalized convoluted gland (visible in 1C) and a venom duct (VD) that opens through the sting (St). B. Detail of framed area in 1A, showing how both filaments fuse into a considerably thinner unpaired filament prior to entering the reservoir sac (white arrow). C. Semithin section through venom reservoir and internalized convoluted gland (CG) in B. sennaarensis alate queen. Note conspicuous supply of muscle fibres (MF). D. Ultrastructural detail (worker) of very thin cuticle-lined reservoir wall. E,F. Longitudinal and transverse semithin sections through the sting base of a worker, showing opening of venom gland duct (VD) and Dufour gland duct (DD). ct: cuticle, F: furcula, FC: fat cells, GS: gonostyli, MF: muscle fibres, NF: nerve fibre, SL: sting lancets.
  • Billen and Al-Khalifa (2018) - Figure 3. A. Longitudinal semithin section through venom gland filament in worker with central lumen and sections through end apparatus (black arrowheads). B. Electron micrograph detail of end apparatus in worker. Note abrupt transition (arrowheads) of thick and continuous cuticle in duct cell (DC) into thin and discontinuous cuticle in secretory cell (SC). Small white arrows indicate disrupted epicuticular inner lining. C. Ultrastructure of secretory cell cytoplasm (queen) with granular appearance because of abundant free ribosomes, and with well-developed Golgi apparatus (GA) and mitochondria (M). D. Detail of nerve fibre (NF) wedged in between gland cells (queen). mv: microvilli, N: nucleus.
  • Billen and Al-Khalifa (2018) - Figure 4. Convoluted gland of B. sennaarensis worker. A. Scanning micrograph showing striated appearance of convoluted gland (CG) after tearing open venom reservoir (RW: reservoir wall). B. Detail of convoluted gland surface (of area indicated by black frame in 4A), arrowheads show openings of gland ducts. C. Detail of inner reservoir wall (of area indicated by white frame in 4A). D,E. Electron micrographs of central (D) and peripheral (E) portion of convoluted gland, showing presence of secretory cells with end apparatus (EA). M: mitochondria, MF: muscle fibres, N: nucleus, VF: venom filaments.

Regional Accounts


Sharaf et al (2018) - This species was found nesting under a stone and foraging on the ground. Several individuals were found in moist soil under a stone next to a date palm tree. In the KSA it has been observed inhabiting sites near human settlements and has an apparent preference of hot habitats (Sharaf & Aldawood, unpublished data)

Saudi Arabia

Al-Khalifa et al (2015) - Collingwood (1985) observed and reported B. sennaarensis in the Kingdom of Saudi Arabia, where it is commonly known as the samsum ant. Later, Collingwood and Agosti (1996) followed and recorded their occurrence in Oman, Yemen and Kuwait, whilst Collingwood et al. (1997) reported it in the United Arab Emirates. B. sennaarensis is considered to constitute a public health hazard in the Kingdom of Saudi Arabia owing to its sting, which has been known to cause cases of fatal anaphylactic shock (Dib et al., 1992, 1995). Al-Shahwan et al. (2006) reported a case of anaphylactic shock and since then several more such cases have been reported following samsum ant stings, some of which were really critical (Al-Anazi et al., 2009). Notwithstanding this negative reputation, however, B. sennaarensis can also be beneficial to humans: Dkhil et al. (2010) found that B. sennaarensis venom has an antiinflammatory effect that may be useful in the treatment of inflammatory skin diseases, whilst Badr et al. (2012) found that B. sennaarensis venom induces apoptosis in certain human breast cancer cells.

In this study, B. sennaarensis was detected in four provinces: ArRiyadh, Jazan, Najran and Eastern Province but was not detected in, Asir, Northern Frontiers, Tabouk, Makkah and Al-Madina. Collingwood (1985) suggested that the Arabian Peninsula is probably the northern limit of B. sennaarensis distribution. Different levels of occurrence of B. sennaarensis in the different regions of Saudi Arabia essentially confirm the non- indigenous status of the species. The population level also appears to depend on the geographical features of the location, with the high altitude of Asir, Makkah and Al-Madina regions, that each stands between 2000 and 3000 m above sea level, appearing to prohibit the occurrence of the species. Provinces such as Jazan and Najran are partially or completely Afrotropical in climate, since B. sennaarensis is indigenous to Africa this would explain their occurrence here. ArRiyadh and the Eastern region, meanwhile, are infested with a large number of ants due to large, frequent transport and heavy exchange of goods (Al-Khalifa et al., 2010). The Tabouk and Northern frontier regions, meanwhile, remain behind in terms of their developmental aspect and geosocial contacts, due to their distant location from the inhabited regions and have thus not yet been reached by these ants (Siddiqui and Al-Khalifa, 2013).


Sharaf et al. (2017) - Brachyponera sennaarensis has invaded a wide range of habitats on Socotra, especially soil that is moist covered with the leaf litter of date palm trees. This species also commonly nests under rocks and objects associated with moist soils. Brachyponera sennaarensis has also invaded the relatively undisturbed valleys of the island where streams and denser vegetation are found. A nest was found under a stone under a dragon blood tree.






The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • sennaarensis. Ponera sennaarensis Mayr, 1862: 721 (w.) SUDAN. Santschi, 1910c: 350 (q.); Forel, 1910c: 245 (m.); Wheeler, G.C. & Wheeler, J. 1971b: 1207 (l.). Combination in Euponera (Brachyponera): Emery, 1901a: 47; in Brachyponera: Wheeler, G.C. & Wheeler, J. 1971b: 1207; in Pachycondyla: Brown, in Bolton, 1995b: 309; in Brachyponera: Schmidt & Shattuck, 2014: 81. Senior synonym of sorghi: Wheeler, W.M. 1922a: 777; Menozzi, 1930b: 80. Current subspecies: nominal plus decolor, ruginota. See also: Arnold, 1915: 73.
  • sorghi. Ponera sorghi Roger, 1863a: 169 (w.) SUDAN. Combination in Euponera (Brachyponera): Emery, 1911d: 84. Junior synonym of sennaarensis: Wheeler, W.M. 1922a: 777.