Mansonia (Mansonioides) africana Theobald

Harbach, Ralph E. & Wilkerson, Richard C., 2023, The insupportable validity of mosquito subspecies (Diptera: Culicidae) and their exclusion from culicid classification, Zootaxa 5303 (1), pp. 1-184 : 113-114

Mansonia (Mansonioides) africana Theobald

subspecies africana ( Theobald, 1901c) —original combination: Panoplites africanus . Distribution: Angola, Benin, Botswana, Burkina Faso, Cameroon, Central African Republic, Côte d’Ivoire, Democratic Republic of the Congo, Equatorial Guinea, Ethiopia, Gabon, Ghana, Kenya, Liberia, Mali, Mozambique, Nigeria, Senegal, Sierra Leone, South Africa, South Sudan, Sudan, Tanzania, Gambia, Uganda, Zambia ( Wilkerson et al. 2021).

subspecies nigerrima Theobald, 1910 —original combination: Mansonia nigerrima (varietal status by Edwards 1913a; subspecific status by Harbach & Howard 2007). Distribution: Senegal, Tanzania, Uganda ( Wilkerson et al. 2021).

Mansonia africana is a well-known African species of the subgenus Mansonioides Theobald, 1907 ; however, like most Afrotropical species of Culicidae , the larval and pupal stages of this species have not been fully described and illustrated. Descriptions of the adults of subspecies nigerrima lack illustrations and are brief and superficial, and the immature stages are unknown.

Theobald (1901c) described Mn. africana (as Panoplites africanus ) from “Quite a number of this species in the collection from Asaba”, a city in southern Nigeria. He added that “The specimens collected at Asaba differ in no respects from those in the other parts of West and Central Africa.” According to Townsend (1990), two syntypes are present in the Natural History Museum, London—“ Malawi: 2 female [head only of 1, on slide], Zomba, Chiromo, Lower Shire.… This is one of the syntypes from ‘West and Central Africa’ referred to generally in the description and listed more fully in Theobald (1901c: 188).” It is not clear to which of the two females this applies, but we assume it is not the one represented by the slide-mounted head. In either case, the localities listed by Theobald (1901c) for his (second) description of Panoplites africanus do not include Asaba [they include Chiromo, Fort Johnstone (now called Mangochi) and Lower Shire (Shire River) in former British Central Africa (present-day Malawi), and Lagos and Old Calabar (contemporary Duke Town) in Nigeria]. It is unfortunate that Stone et al. (1959) and Knight & Stone (1977) did not arrange Theobald’s early publications in strict chronological order. Theobald (1901c) [??/09/1901] predates Theobald (1901c) [12/11/1901] by two months; consequently, it seems that the specimens from Asada, Nigeria are non-extant and the two “ syntype ” females have no taxonomic status.

Theobald (1910) described Mansonia nigerrima based on a single female from Mpuma, Uganda (Mpuma, now known as Mpuma-Luga, is a city in the Mukono District, Central Region, located about 28 km east of Kampala). Edwards (1913a) placed Ma. major Theobald, 1903a and Mn. nigerrima in synonymy with Mn. africana (as Mansonioides africanus ) but then, seemingly reluctantly, treated nigerrima as a variety, saying: “ M. nigerrima may perhaps rank as a good variety; it is much darker than the type: the thorax is darker, with hardly a trace of pale markings; the dark scales of the wings are much more numerous than the light, and the white rings at the bases of the hind tarsal joints are much narrower than in typical M. africanus . The male genitalia, however, do not differ in any way. This form has up to the present only been found in Uganda.” Edwards (1932a, 1941) was the only taxonomist post-Theobald (1901c, 1901d) to recognize and treat nigerrima as a separate form. Later workers, Hopkins (1936, 1952), da Cunha Ramos & Ribeiro (1975), Service (1990), Jupp (1996) and Becker et al. (2020), only recognized the nominotypical form, perhaps because they considered nigerrima to merely be a morphological variant. These authors were, of course, with the possible exception of Becker et al., unaware that Harbach & Howard (2007) had raised nigerrima to subspecific rank based on provisions of the International Code of Zoological Nomenclature: “Despite Edwards’ (1913a) apparent reluctance to treat nigerrima as a variety, implying that it should perhaps be regarded as an infrasubspecific entity, it is deemed to have subspecific rank because it was adopted (originally) as the valid name of a species before 1985 (Article 45.6.4.1).” In the absence of concrete morphological differentiation and evidence of geographical isolation, we believe that the action taken by Harbach & Howard, based merely on provisions of the Code, was ill-considered. Of course nigerrima could possibly be a separate species, but until this is conclusively proven, based on comparative morphological study of all life stages and molecular assessment, we believe it is prudent to consign nigerrima to synonymy: nigerrima Theobald, 1910 , junior subjective synonym of Mansonia (Mansonioides) africana ( Theobald, 1901c) . Consequently, Mansonia nigerrima should be removed from the species of Mansonia listed in the Encyclopedia of Life.

As indicated above, contrary to Wilkerson et al. (2021), Mn. major Theobald, 1903a was synonymized with Mn. africana by Edwards (1913a), not Edwards (1932a), who stated that “ M. major was described from a flattened, but typical female specimen [of Mansonioides africanus ].” There is no reason to doubt this synonymy, and it is retained, along with Mn. nigerrima , as a synonym of Mn. africana .