Bothroponera kruegeri

Joma and Mackay (2017) - Bothroponera kruegeri has been collected from different habitats in Africa, principally farmlands and tropical forests. Colonies of this ant were studied extensively to investigate the gamergate number (workers with the ability to reproduce), control over reproduction (Wildman and Crewe, 1988) and qualitative relations of egg size, egg production and colony size (Villet 1990). Bothroponera kruegeri has a specific form of regulation of gamergate numbers in their colonies. There is a single gamergate present in B. kruegeri colonies, which had 3 to 6 mature oocytes (Peeters and Crewe, 1985; Peeters and Crewe, 1986; Wildman and Crewe, 1988; and Peeters and Higashi, 1989). Moreover, B. kruegeri gamergates are able to produce between 0.5-3 eggs per day (Wildman and Crewe, 1988). Bothroponera kruegeri (B. rhodesiana) builds several entrances for their nest and the adjacent area contains loose earth (Wheeler, 1922b; Arnold, 1915).

Identification
Joma and Mackay (2017) - Worker - The main distinguishing character of Bothroponera kruegeri is that it is the largest ant among the Bothroponera sulcata species complex (total length 11.75 - 12.55 mm). The mandibles are narrowed and covered with fine striae and have about 8-9 teeth. The anterior medial margin the clypeus is convex, with a medial raised area that rarely forms a short elongate groove anteriorly (often absent). The frontal lobes are divided by a shallow frontal furrow, which is not continued to the irons.

The head, pronotum, mesopleuron, propodeum, petiole and postpetiole are roughly sculptured and moderately shiny. The lower lateral margins of the pronotum are straight and form angular inferior and anteroinferior pronotal processes. The dorsopropodeum broadly curves posteriorly to gradually reach the articulation point with the petiole between the propodeal lobes.

The entire surface of the body is hairy and black.

The worker of Bothroponera kruegeri is similar to those of the B. sulcata complex members except for some unique characters such as the large total length (11.75 - 12.55 mm total length for the worker and 10.25 mm for the male), the number of mandibular teeth (8-9 teeth, which is the largest number among the B. sulcata complex species), the anterior raised area of the clypeus and the postero-dorsopropodeal shape. The anterior medial raised area of the clypeus is convex in all of the B. sulcata complex members, but this area forms a smooth and shiny raised medial area without a clypeal carina in Bothroponera crassa, a longitudinal shiny groove not well developed or even absent in Bothroponera ilgii, Bothroponera picardi, Bothroponera silvestrii and Bothroponera ryderae, a narrowed longitudinal smooth strip usually without a groove in B. silvestrii and B. pilosuperficia. In Bothroponera soror, the clypeus has a single medial raised area that forms a shiny, completely or partially striated area or a smooth shiny narrowed groove. Conversely the anterior raised area of the clypeus of B. kruegeri forms a raised sculptured area on the upper part and tiny shiny area that seems to have a small depression close to the lower clypeal margin. The dorsopropodeum forms a broadly curved outline the connects gradually with the posteropropodeum and reaches the insertion point of the petiole. The dorsopropodea of B. silvestrii, B. crassa, B. ilgii, and Bothroponera notaula are more strongly curved than that of B. kruegeri to form an angle with the posteropropodeum. The dorsopropodeum forms a strong angle with the posteropropodeum, which strongly slopes posteriorly in B. soror, B. silvestrii, B. picardi, Bothroponera ancilla, B. ryderae and B. pilosuperficia.

Male - The head is nearly circular, excluding the mouth parts and the mandibles. The ocelli are relatively large. The scape is shorter and thicker than the second funicular segment, twice the length of the pedicel. The notauli are weakly developed on the dorsum of the scutum. The scutum is distinguished by three brown areas, two are around each of the parapsidal sutures and one is a triangular spot between the notauli. The medial area, between the brown spots is pale brown or yellow in color. The scutellum is triangular and elevated in dorsal view. The metanepisternum is well distinguished while the metakatepisternum is triangular and poorly developed. The dorsopropodeum gradual slopes posteriorly to reach the insertion of the petiole. The petiolar node is small, its width is less than the width of the dorsopropodeum and its height is less than that of the postpetiole height and has a pointed apex. The postpetiole is rounded anteriorly. The pronotum, scutum, scutellum, propodeum, petiole and postpetiole are roughly sculptured.

The entire body is covered with fine short dense hairs and scattered long hairs on the dorsum of the scutellum, metanotum, propodeum, petiole and postpetiole.

The surface color is mostly light brown and yellowish.

The male of Bothroponera kruegeri can be compared with other known males of the B. sulcata species complex, including those of B. crassa, B. ilgii, B. silvestrii, B. notaula, B. ryderae and B. soror. The total length of B. kruegeri is 10.25 mm which is the largest body length among other male castes, including B. soror (6.45 - 7.45 mm), B. crassa (5.90 - 7.50 mm), B. notaula (5.60 - 7.90 mm), B. ryderae (6.45 mm) and B. silvestrii (4.70 - 5.10 mm). The total length of B. ilgii is unavailable as the gaster is missing in the only available male type specimen. The notauli are absent or weakly defined in B. kruegeri similar to those in B. crassa and B. ilgii while they are present in B. soror, B. silvestrii, B. notaula and B. ryderae. The ocelli are large in B. kruegeri, B. notaula and B. crassa, but they are small in B. soror and the type specimen of B. ilgii, similar to that in B. silvestrii and B. ryderae. The entire surface of B. kruegeri is rough, similar to that of B. crassa and B. ilgii, but in B. soror the mesosoma and petiole are roughly sculptured with punctures. The dorsopropodeum gradually slopes posteriorly in B. kruegeri as in B. crassa, B. ilgii, B. silvestrii and B. notaula, but in B. soror it is strongly curved posteriorly similar to that in B. picardi, B. silvestrii, B. ancilla, B. ryderae and B. pilosuperficia.

Distribution based on Regional Taxon Lists
Afrotropical Region: Kenya, Mozambique, South Africa, United Republic of Tanzania, Zimbabwe.

Nomenclature

 *  kruegeri. Pachycondyla (Bothroponera) kruegeri Forel, 1910a: 28 (w.) SOUTH AFRICA.
 * Combination in Bothroponera: Wheeler, W.M. 1922a: 22.
 * Combination in Pachycondyla: Brown, in Bolton, 1995b: 306.
 * Combination in Bothroponera: Schmidt & Shattuck, 2014: 77.
 * Senior synonym of asina, rhodesiana: Joma & Mackay, 2017: 23.
 * See also: Arnold, 1915: 56.
 * asina. Pachycondyla (Bothroponera) asina'' Santschi, 1912b: 153 (w.) KENYA.
 * Combination in Bothroponera: Wheeler, W.M. 1922a: 770.
 * Combination in Pachycondyla: Brown, in Bolton, 1995b: 303.
 * Combination in Bothroponera: Schmidt & Shattuck, 2014: 77.
 * Subspecies of kruegeri: Santschi, 1914e: 4.
 * Junior synonym of kruegeri: Joma & Mackay, 2017: 23.
 * rhodesiana. Pachycondyla (Bothroponera) kruegeri var. rhodesiana'' Forel, 1913a: 109 (w.) ZIMBABWE.
 * Arnold, 1915: 57 (m.).
 * Combination in Bothroponera: Wheeler, W.M. 1922a: 770.
 * Combination in Pachycondyla: Brown, in Bolton, 1995b: 308.
 * Combination in Bothroponera: Schmidt & Shattuck, 2014: 77.
 * Junior synonym of kruegeri: Joma & Mackay, 2017: 23.

Worker
Joma and Mackay (2017) - (n=9), B. kruegeri measurements: HL 2.30 - 2.40, HW 2.00 - 2.10, ML 1.40, EW 0.40, EL 0.60, SL 2.00 - 2.20, FL 3.00 - 3.10, WL 3.70 - 3.80, WPL 4.60 - 4.70, PL 1.00, PW 1.10, PH 1.50 - 1.60, CI 86.95 - 87.50, OI 28.57 - 30.00, Mandl 58.33 - 60.86, SI 100.00 - 104.76, Peti 110.00. B. asina measurements: HL 2.20, HW 2.00, ML 1.30, EW 0.40, EL 0.50, SL 1.90, FL 3.00, WL 3.70, WPL 4.50, PL 0.90, PW 1.20, PH 1.50, CI 90.90, OI 25.00, Mandl 59.09, SI 95.00, Peti 133.33. B. rhodesiana measurements: HL 2.50 - 2.70, HW 1 .95 - 2.20, ML 1 .50 - 1 .55, EW 0.45, EL 0.65 - 0.70, SL 2.10 - 2.25, FL 3.25 - 3.40, WL 3.60 - 4.20, WPL 4.40 -5.00, PL 1.00- 1.05, PW 1.15- 1.35, PH 1.65 - 1.95, CI 78.00 - 81.48, OI 33.33 - 31.81, Mandl 57.40 - 60.00, SI 102.27 - 107.69, Peti 115.00 - 128.57. Compound eyes relatively large; malar space length 0.45 - 0.50 mm, area from upper edge of eye to upper margin of posterior lobe 0.85- 0.95 mm; pronotal humerus rounded anteriorly with straight ventral margin (side view) that forms sharp anteroinferior and inferior pronotal processes; dorsopropodeum slightly curved, posteropropodeum slightly concave, with slight medial depression, seen from dorsal or from posterior view; entire surface of body covered with fine hairs; dorsum of pronotum, propodeum, petiole and postpetiole covered with few moderately short (0.20 mm) erect scattered hairs; head covered with few short (0.10 - 0.20 mm) erect hairs; short (0.10-0.15 mm) erect hairs scattered on legs and scape; hairs on ventral surface of head moderately long (0.20 - 0.35 mm); color of entire body black; tibia, clypeus and scape brownish black, tarsus, funiculus and mandibles reddish brown.

Male
Joma and Mackay (2017) - (n=l), HL 1.45, HW 1.05, ML 0.35, EW 0.60, EL 0.95, SL 0.30, FL 5.90, WL 3.45, WPL 4.35, PL 0.75, PW 0.70, PH 1.15, CI 72.41, OI 90.47, Mandl 24.13, SI 28.57, Peti 93.33. Total length 10.25 mm; eyes large, cover most of sides of head; scape shorter (0.35 mm), twice as long as pedicel length (0.15 mm) and thicker than second funicular segment (length 0.55 mm); pronotum quadrate laterally and rounded anteriorly; scutellum triangular, elevated in dorsal view; Longer hairs (0.20 - 0.35 mm) scattered on dorsum of scutellum, metanotum, propodeum and petiole; hairs on dorsum of postpetiole range in length from 0.25 - 0.30 mm; long hairs appear on suture between pronotum and scutum.

Type Material
Joma and Mackay (2017) - South Africa: Valdezia, Transvall, 23°6’0’’ S; 30°11’0’’ E, P. Bethould collector, Pachycondyla (Bothroponera) kruegeri Forel, 1910a, new species (2w, lectotype upper specimen, paralectotype lower specimen [here designated and type locality restricted] ). 6 workers: Kenya: Afrique orientale anglaise, Nirobi, Nairobi Area, 1°17’0’’ S; 36°49’0’’ E, Pachycondyla (Bothroponera) asina Santschi (1w, holotype, NHMB). Zimbabwe: Bulawayo, 2 Bulawayo Fan., 1912. 20°9’0’’ S; 28°35’0’’ E, Bothroponera kruegeri var. rhodesiana Forel, G Arnold, (3w, lectotype upper specimen, paralectotype lower specimens [here designated] NHMB).