A Revision of the Pseudotropheus Elongatus Group with a Description of a New Genus Chindongo and Seven New Species

Lake malawi is an African lake surrounded by Malawi, Tanzania, and Mozambique, and is known for its endemic haplochromine species flock, most notably, the rock-dwelling cichlids known as mbuna. Mbuna include genera such as Metriaclima, Tropheops, Cynotilapia, and Pseudotropheus. Cynotilapia is one of the most primitive group of mbuna, and the species of Cynotilapia differ in one main anatomical characteristic from those of Metriaclima, Tropheops, and Pseudotropheus by possessing widely spaced conical teeth in the outer jaws while the others all have bicuspid teeth. Metriaclima and Tropheops are genera split from Pseudotropheus recently on the basis of their different feeding behavior and several morphological characteristics including the angle of the vomer and tooth structures. A number of unique populations of elongate mbuna in Metriaclima, Tropheops, and Cynotilapia are not formally described or grouped into the Pseudotropheus elongates complex. The purpose of this study is to describe several members of this complex that belong to Metriaclima, Tropheops, Cynotilapia, or Chindongo, a new genus. Morphological and meristic data were collected for 255 specimens from 14 collections from Lake Malawi. Morphological differences were analyzed using a sheared principal component analysis (SPCA) of the morphometric data and a principal component analysis (PCA) of the meristic data. Different color forms and feeding behaviors were also investigated in this study. This study resulted in the description of a new genus, Chindongo, with its type species C. bellicosus, and six new species belonging to the existing genera Metriaclima, Tropheops, and Cynotilapia: M. flavicauda, M. usisyae, T. kumwera, T. biriwira, T. mtambokuda, and C. chilundu. The new genus and species were distinguished and described based on color patterns, morphometric, meristic, and on ecological differences. They were also compared with, and distinguished from nearby populations having similar pigmentation patterns or similar ecological niches. An artificial dichotomous key is provided to each genus.