Anopheles obscurus ( Grünberg, 1905 )

Coetzee, Maureen, 2022, Literature review of the systematics, biology and role in malaria transmission of species in the Afrotropical Anopheles subgenus Anopheles (Diptera: Culicidae), Zootaxa 5133 (2), pp. 182-200 : 188-189

Anopheles obscurus ( Grünberg, 1905)

1905. Myzorhynchus obscurus Grünberg

1907. Myzorhynchus strachanii Theobald , synonym

1924. Anopheles obscurus of Christophers

1932. Anopheles obscurus var. nowlini Evans

1980. Anopheles nowlini White , synonym

TYPE LOCALITY: Cameroon .

DESCRIPTION:

Wing length: 5.0 mm.

Wing ( Fig. 6a ): Sector, subcostal and preapical pale spots present; apical pale fringe spot between R 4+5 and M 1+2; basal 0.5 of A1 dark.

Maxillary palpus ( Fig. 6b ): Shaggy, all dark.

Legs ( Fig. 6c ): Black, usually with minute but distinct pale bands or spots at apices of all leg segments except tarsomeres 4 and 5 of the fore- and midlegs.

Variation: Pale leg markings variable. Sometimes reduced to such an extent that legs appear completely dark. Conversely, there are very occasional specimens showing very conspicuous pale markings, which in extreme cases occur both basally and apically, and hindtarsomere 5 may even be entirely white ( Fig. 6c ). In addition, amount of pale scaling on the wings also variable, in particular there may be a humeral pale spot at base of costa.

LARVAL HABITAT: Natural collections of clear water with aquatic and semi-aquatic vegetation, such as swamps, ponds, backwaters of streams, springs, ditches and rice fields.

ADULT BIOLOGY: Gillies & de Meillon (1968) described this as a forest species having little contact with humans, with small numbers being caught on human bait outdoors at night. In Gabon, Makanga et al. (2017) collected specimens in wildlife reserves. The blood meal of one An. obscurus was from the ungulate Cephalophus callipygus , known as Peters’s duiker. Three out of 21 females were found infected with ungulate haemosporidian parasites. At a chimpanzee rehabilitation centre in the Republic of the Congo, Bakker et al. (2020) used traps baited with odours from chimpanzees, humans and cows to collect mosquitoes over a four– month period. Over 5,000 An. obscurus were collected but no preference was shown for any one of the odours, with mean collections of 29.9, 27.0 and 28.3 mosquitoes per bait per trap-night, respectively.

DISTRIBUTION: Primarily a species of West African and Congo forests, ranging from Sierra Leone through Cameroon and the DRC to Uganda, South Sudan and Ethiopia; southward to Angola and also Pemba (Ngezi forest) in Tanzania ( Gillies & de Meillon 1968).

Figures

FIGURE 6. Anopheles obscurus: a, wing; b, palpomere; c, hindleg showing variation (from Gillies & de Meillon 1968; Gillies & Coetzee 1987).