Gnathonemus angolensis Boulenger, 1905 , p. 458

Kramer, Bernd, Skelton, Paul, Bank, Herman Van Der & Wink, Michael, 2007, Allopatric differentiation in the Marcusenius macrolepidotus species complex in southern and eastern Africa: the resurrection of M. pongolensis and M. angolensis, and the description of two new species (Mormyridae, Teleostei), Journal of Natural History 41 (9 - 12), pp. 647-708 : 680-681

Gnathonemus angolensis Boulenger, 1905, p. 458 . Origin, Quanza River, Angola.

Gnathonemus macrolepidotus angolensis: Poll and Gosse 1963, p. 93 .

Marcusenius angolensis: Taverne 1971a, p. 103 ; Taverne 1971b, p. 134; Taverne 1972,

p. 166.

Marcusenius macrolepidotus angolensis: Gosse 1984, p. 86 . ‘‘Distribution: Angola ( Zaïre basin and Upper Zambesi), Zaïre, (Upper basin)’’. In consequence, Skelton et al. (1985) state that Marcusenius macrolepidotus angolensis applies to the Upper Zambezi form.

Type specimens. Holotype (unique): BMNH 1905.5.29.64.

Type locality. Angola: Quanza River (no. 2, Figure 4 ) .

The present subspecies M. macrolepidotus angolensis ( Poll and Gosse 1963) refers to the single specimen of G. angolensis Boulenger 1905 from the Quanza River in Angola. The fishes of the upper Quanza appear to be related to the fishes of the Zambezi basin and to the Cunene ( Trewavas 1973; P. Skelton, unpublished), and G. angolensis was therefore included in our anatomical comparisons.

Diagnosis. Together with M. moeruensis , most extreme nA (33) count for all specimens of the present study, maximum nD (26) count for whole study, longest LA, long LD, low CPL /SL (documented Table XI), shorter chin appendix than M. moeruensis .

Description. See Boulenger (1905, p. 458). Gnathonemus angolensis (N 51) exceeded even outliers in LA, nD and nA, and the 90th percentile of LD in M. altisambesi (N 589). With nA533, well beyond the maximum observed in large sample of M. altisambesi (nAmax 530; Table XI).

Colour in preservation. A homogeneous brown-ochre, but Boulenger (1905) noted ‘‘brown above, silvery white beneath; a few irregular dark brown blotches on the body; fins dark brown’’.

Ecology. Boulenger (1905) is no more specific than ‘‘… from the Quanza River’’. However, Boulenger (1910) cites Dr. J. W. Ansorge as reporting that he made his collection from rivers, lakes and swamps produced from overflows of these rivers during the rainy season (see next paragraph).

Distribution. ‘‘… from the Quanza River’’ (locality not given in Boulenger 1905). Boulenger (1910) states that Dr. Ansorge’s ‘‘collection was made from three rivers (the Quanza, the Luculla, and the Bengo), …’’, and further below, ‘‘Exploration of the Quanza River at Cunga, Dondo, and Cambambe gave also valuable results’’. The description in Boulenger (1910) refers to the terminal section of the Quanza in or near the coastal lowland of northern Angola; therefore, this region is the likely origin of G. angolensis Boulenger, 1905 .

Relationships. Poll and Gosse (1963, p. 93) have synonymized Gnathonemus angolensis Boulenger, 1905 with M. macrolepidotus as the subspecies M. m. angolensis (‘‘ Gnathonemus angolensis est une espèce qui doit être considérée comme sous-espèce de Gnathonemus macrolepidotus et la référence d’ angolensis est par conséquent comprise dans celle de macrolepidotus ’’), a status which we do not confirm. Its combination of meristic characters (nA and nD highest, SPc lowest; Table XI) sets G. angolensis (and also G. moeruensis , of which Boulenger 1915 states that it is ‘‘très voisin’’ to G. angolensis ) well apart from all other bulldog samples we were able to study. ‘‘Allied to G. senegalensis, Stdr ; distinguished by larger scales’’ ( Boulenger 1905). Gnathonemus senegalensis is the West-African species Marcusenius senegalensis (Steindachner, 1870) . Boulenger did not state why he recognised G. moeruensis as distinct from Gnathonemus angolensis when both are so similar. However, he did note an only feeble mental swelling in G. angolensis ( Boulenger 1905) and ‘‘un renflement sphérique très developpé au menton’’ in G. moeruensis ( Boulenger 1915) .

Figures

Figure 4. Partial map of southern Africa showing the sampling localities for Marcusenius sp. Only the larger rivers are shown. Numbers code for origins of samples: (1) Tete on the Lower Zambezi (M. macrolepidotus, as for types); (2) Quanza River (G. angolensis, type; exact sampling site unknown); (3) Lake Mweru (G. moeruensis, type); (4) Pongola River near Paulpietersburg (G. pongolensis, type); (5) Sabie River; (6) Crocodile River; (7) Groot Letaba River (Limpopo System); (8) Blyde River (Limpopo System; (9) KwaMaZulu stream, Mhlatuze System (not shown); (10) Pongola River, more downstream compared to (4); (11) Lisikili, Upper Zambezi; (12) Kwando River, (13) Okavango System; (14) Tana River; (15) Buzi River System; (16) Pungwe River; (17) Lower Zambezi, delta region; (18) Mulela River; (19) Rovuma River System.