Serranochromis altus, a New Species of Piscivorous Cichlid (Teleostei: Perciformes) from the Upper Zambezi River

Abstract

A new cichlid species, Serranochromis altus, from the Upper Zambezi River is described. It is sympatric with its deep-bodied sister species, S. angusticeps, within the Upper Zambezi and Kafue River drainages. Both immatures and adults of the new species can be distinguished from S. angusticeps on the basis of morphometric characters and color pattern, including the absence of distinct speckles on the face and chest and eye stripes that are diagnostic of the latter. Serranochromis altus has a shorter snout, larger eyes, wider head features, and longer pectoral fins than S. angusticeps of similar size. Both sexes of the new species mature at a larger size and appear to attain larger maximum sizes than S. angusticeps. During the low water period, S. altus inhabits deep regions of the main Zambezi River channel and feeds primarily on nocturnal mormyrid and schilbeid fishes. In contrast, S. angusticeps dwells in densely vegetated regions of quiet backwaters and lagoons of the Barotse floodplain where it ambushes small characids and cyprinids.