Subspecies in the Polypterus palmas Complex (Brachiopterygii; Polypteridae) from West and Central Africa

Abstract

DURING recent fieldwork in Guinea, West GGT collected large numbers of Polypterus specimens. These specimens could not be readily identified in the key by Gosse (1990) for West African Polypterus species. In that key, two groups of Polypterus were recognized. In the first, the pectoral fin reaches the first dorsal finlet; both jaws are of equal length, or the lower jaw is longer; and the lateral-line scales are grooved in adult specimens, with a notched posterior border. In the second group, a distinct gap is present between pectoral and dorsal fin; the upper jaw is the longer; and the lateral-line scales in adults lack a posterior notch and are not grooved. Our Guinea specimens clearly belong to the second group consisting of P. senegalus senegalus Cuvier, 1829, and P. palmas Ayres, 1850. The distinct blotches irregularly placed on the flanks, easily distinguish our adult specimens from the uniformly colored adult P. senegalus and indicate affinities with P. palmas although differences, amongst others, in predorsal scale counts, were noted between P. palmas and the Guinea specimens. Ayres (1850) described P. palmas on a single specimen from Cape Palmas, West Africa, a locality near the mouth of the Cavally River, the border between the Ivory Coast and Liberia (Fig. 1, locality 15). Two nominal species have subsequently been synonymized with P. palmas. Polypterus buettikoferi, described by Steindachner (1891), was soon thereafter synonymized by that author (1894) with P. palmas. Polypterus lowei Boulenger (1911) was redescribed by Poll (1941) as a subspecies of P. retropinnis Vaillant, 1886, endemic to Liberia. Gosse (1988), in contrast, synonymized P. lowei with P. palmas. Polypterus palmas has also been reported from the Zaire basin in Central Africa. Poll (1954) considered specimens from the Zaire basin as a subspecies, P. p. congicus. Gosse (1988) discussed the status of P. palmas and proposed P. polli as a replacement name for P. p. congicus which he considered a nomen nudum. In the same paper, Gosse (1988) referred to an unpublished master's thesis of Coenen (1978) in which the synonymy between P. lowei and P. palmas had been retained and in which a possible recognition of P. buettikoferi was suggested. This suggestion, however, was based on the study of only three specimens, not including any types. To resolve the systematic status of the P. palmas complex and correctly identify the Guinean specimens, a detailed morphometric study of the available material belonging to the P. palmas complex of both West and Central Africa was undertaken.