Dorylus nigricans Illiger 1802
Year: 2026
Type: article
Abstract: Dorylus nigricans Illiger, 1802 Figs 6 A – C, 7 A, 11, 12, 15, 16, 24, 25, 27 Dorylus nigricans Illiger, 1802: 188. Two male syntypes, Sierra Leone, collector unknown (“ Hellwig’s collection ”), ZMHB [examined]. Lectotype male (above referred to as syntype A), here designated, unique specimen identifier of lectotype: MfN 9e9e77. Anomma pubescens Roger, 1861: 47. Holotype worker, Liberia, collector F. E. Guérin-Méneville (ZMHB) [examined]. Junior synonym of D. nigricans (see Emery 1895). Combination in Dorylus (Anomma): Emery 1895: 710. Combination in Anomma: Menozzi 1942: 165. Combination in Dorylus: Borowiec 2016: 117. Anomma arcens Westwood, 1847: 17. Thirty worker syntypes, Liberia, collected by Savage at Cape Palmas, OUMNH HYME 1178 / 1-30 [examined]. New synonymy. Annotation. A comprehensive taxonomic history of this species can be found in AntCat. Other material examined. Ghana: • Bobiri (Lat. 6.68, Long. - 1.35, 3 males, 15 worker samples, L. Davis, L. Fisch, M. Moffett & W. H. Gotwald Jr., CSAC), • New Tafo (Lat. 6.22, Long. - 0.37, 2 worker samples, L. Fisch & W. H. Gotwald Jr., CSAC). Guinea: • Bossou (Lat. 8.65, Long. - 11.8,> 30 worker samples, T. Humle, K. Koops, Y. Sugiyama), • Seringbara (Lat. 7.64, Long. - 8.41,> 100 worker samples, K. Koops). Ivory Coast: • Djouroutou (Lat. 5.40, Long. - 7.20, 6 worker samples, J. Lapuente), • Lamto (Lat. 6.22, Long. - 5.03, 2 males, 5 worker samples, 1 worker sample with queen, M. Kone, J. M. Leroux, J. Levieux, J. K. A. van Boven, CASC, MCZC, RMCA), • Taï National Park (Lat. 5.84, Long. - 7.32, 10 males,> 20 worker samples, T. Deschner, J. Lapuente, F. Leendertz, L. Luncz, A. Meier, Y. Möbius, C. Schöning, CASC, SMNG; • 1 worker, Kronauer et al. 2007 / 7, 1 male, Kronauer et al. 2007 / 14, NHMD). Liberia: • Charlesville (Lat. 6.20, Long. - 10.38, 3 males, D. H. Kistner, RMCA), • East Nimba (Lat. 7.43, Long. - 8.57, 14 worker samples, S. Maroccoli & S. Jones, SMNG), • Grebo (Lat. 5.48, Long. - 7.56, 54 worker samples, S. Marrocoli, SMNG), • 20 other sites in Liberia (from nationwide survey, see Tweh et al. 2014). Notes. After the species was described based on the males collected in Sierra Leone, Savage (1849) discovered winged males in a driver ant colony in Gabon and considered them to belong to the same species. Since then, several authors have jumped to the conclusion that Dorylus nigricans males may be conspecific with driver ant forms collected at other locations across Africa. For example, Emery (1895) considered Dorylus nigricans males to be conspecific with Anomma burmeisteri workers, while Forel (1912) described a small queen from central Uganda under the name D. nigricans. Driver ant workers from other parts of Africa that resembled the West African Anomma burmeisteri were likewise described as subspecies of D. nigricans (e. g. “ Dorylus nigricans sjöstedti (sic!) ” by Emery (1899)). In all these instances the logic behind these decisions remains unconvincing because conspecificity can only be unequivocally demonstrated in one of the ways mentioned in the Introduction. The phrasing in Illiger’s original description from 1802 is somewhat ambiguous. We considered the possibility that he examined more than just two specimens and designated all of them as types, but no further specimens are present in the ZMHB collection. Bolton (2026) mentions that a part of Illiger’s collection is kept at the Staatliches Naturhistorisches Museum at Braunschweig (Germany), but this collection does not contain any further type specimens either (Claudia Kamcke, pers. comm. 27 August 2025), so that we could only work with the two specimens available. The results presented above allow us to clarify the taxonomy of this species. We explain the argument behind synonymising D. nigricans arcens (Westwood, 1847) under D. nigricans Illiger, 1802 in a set of summary statements: Dorylus nigricans Illiger, 1802 is a name based on a male from Sierra Leone. Based on our morphometric analyses (Fig. 17) we consider the two male syntypes in ZMHB to belong to different species: syntype A falls within the variation of modern West African driver ant males from Charlesville (Liberia), Bobiri (Ghana), Lamto and Taï (Ivory Coast) with translucent wings, while the smaller syntype B with smoky-brown wings differs substantially from them. We thus conclude that syntype A is conspecific with the males with translucent wings. We designate syntype A as the lectotype of Dorylus nigricans Illiger, 1802, thereby fixing the name to a single name-bearing specimen for the first time. Syntype B becomes the paralectotype and loses name-bearing function for D. nigricans; its species identity remains to be resolved. The DNA sequence data from sympatric specimens from Taï National Park (Fig. 18) show that the males which we consider to be conspecific with syntype A are associated with the worker form with relatively longer legs and antennae. The morphological examination of the worker syntypes of Anomma arcens Westwood, 1847 in OUMNH revealed that the workers with relatively longer legs and antennae are conspecific with those syntypes. When combining steps 1–5, we conclude that the worker form historically called A. arcens is conspecific with the male-based D. nigricans. Because D. nigricans Illiger, 1802 has priority over A. arcens Westwood, 1847, acceptance of this association makes D. nigricans the valid name for this species and A. arcens a junior synonym. Description of the queen. This description is based on one queen associated with workers from the Van Boven collection in the RMCA (collection number Van Boven 2768). It was collected from a nest at Lamto in Ivory Coast probably on August 11, 1965 (Van Boven and Levieux 1970). Habitus: Fig. 25 A, overall darker and larger than D. burmeisteri. Total length: 4.130 cm. Head: Fig. 25 C, H W = 5.883 mm, HL = 4.018 mm, SL = 1.916 mm, lateral sides orange, dark brown on dorsal and ventral side, surface appears slightly dull due to microreticulation, foveola evenly distributed over whole surface of head and at least as deep as wide (diameter 29 µm), no pilosity present; Antenna: eleven antennomeres, funicular antennomeres dark orange and scape somewhat darker, antennal fossae pronounced, deeply impressed and round in shape, median line at the lower half V-shaped, circular impression in the upper third of median line, similar to “ ocellus-like body ” in D. gribodoi (Schöning et al. 2008 b), clypeus with some setae, labrum with small median notch and some hairs, mandibles with few setae at inner side; subapical teeth missing and apical tooth slightly pointing medially, small lateral indentation like in ocular area of males, posterior angles of head drawn out backwards and ventrally. Mesosoma: Fig. 25 A, B, P W = 3.618 mm, PropW = 4.192 mm, HFL = 3.923 mm, colour similar to dorsal areas of head, dark brown, lighter close to sutures between segments, pronotal suture slightly impressed, ventral margin of pronotum with small hairy ridge, propodeum rectilinear, spiracle rim not visible in dorsal view; at metanotal groove with medial spine projecting backwards; surface sculpture similar to head, with microreticulation and foveolae; pleura and coxae of pro-, meso- and metathorax with yellowish pilosity at junctions, terminal segments of legs missing. Petiole: Fig. 25 A, B, PeW = 6.990 mm, blackish brown in colour, surface sculpture similar to head and mesosoma, no setae and without pilosity, posterior lateral lobes very conspicuous in dorsal view. Gaster: Fig. 25 A, B blackish brown, shinier than head and mesosoma but otherwise similar, with numerous scratches of unknown origin. Genitalia: Fig. 25 D, typical driver ant hypopygium similar to Gotwald (1982: 167). Biology. In our surveys, the species was found from Liberia to Ghana. The type locality is further to the West in Sierra Leone. Based on the information of habitat types at the collection localities we inferred that the species is restricted to moist forest habitats. This species is also regularly consumed by chimpanzees at Bossou, Seringbara, and Taï (Schöning et al. 2008 c; Koops et al. 2015). As mentioned above, Leroux, unbeknownst to him, was dealing with two species in his long-term field study at Lamto. The colonies designated 2 ” 0 ”, 2 R, 52 B, IB, and IE by him belong to D. nigricans.
Language: English
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7204154898