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A species of haplochromine cichlid fish of the genus Diplotaxodon Trewavas, endemic to Lake Malaŵi is described: Diplotaxodon dentatus, new species. All eight type specimens were trawled together off Thumbi East Island in the Southeastern arm of the lake at 73 meters in 1985. They were initially identified as D. argenteus because the teeth on the oral jaws were fully exposed with a closed mouth. The shorter snout length of D. dentatus (26.6–29.2 % HL) clearly separates it from D. argenteus (31.7–34.2 % HL). A plot of a principal components analysis further supports the separation of D. dentatus from D. argenteus.

Two species of haplochromine cichlid fishes of the genus Diplotaxodon Trewavas, endemic to Lake Malaŵi are described: Diplotaxodon longimaxilla, new species, and Diplotaxodon altus, new species. Diplotaxodon altus is diagnosed from other species in the genus based on body depth (35.1–37.8% SL), number of gill rakers (21–26), and a smaller cheek depth (18.2–20.0% HL). Diplotaxodon longimaxilla is delimited from other Diplotaxodon spp. based on body depth (28.9–32.4% SL), horizontal eye diameter (HED 27.1–32.1% HL), smaller cheek depth (15.2–19.4% HL), and number of lateral-line scales (35–38). Other authors have indicated that several other Diplotaxodon spp. occur, but too few specimens were available to permit detailed comparisons. The two new species occur sympatrically at depths of between 40–130 m. Specimens of Diplotaxodon altus were sampled from nets deployed at night using light attraction, while specimens of D. longimaxilla were sampled from nets operated both at night and day. We further ...

Pseudotropheus livingstonii and P. elegans are two sand-dwelling cichlid species that belong to the so-called mbuna, a group of predominantly rock-dwelling haplochromines of Lake Malaŵi. The identity of these two species has confused taxonomists for almost a century until a recent rediscovery of representatives of P. elegans close to its type locality. New diagnoses for both species are provided.

We have observed a dramatic decrease in the abundance of snail-eating fishes and an increase in the prevalence of schistosomiasis among village residents and expatriate tourists at Lake Malawi, Africa, over the past two decades. We hypothesized that these observations were linked by a cause-and-effect relationship and that the observed decrease in fish molluscivores permitted an increase in the abundance of snails that are intermediate hosts to schistosomes; we proposed a sampling protocol to determine these relationships. Initially, we thought that intensive study of the interactions among fish, intermediate-host snails, and human schistosomes in southern Lake Malawi could be applied to other areas throughout the lake. More than two-thirds of the cichlid species in Lake Malawi are undescribed, the taxonomy of the Bulinus snails is poorly known, and not all strains of Schistosoma hematobium have been identified. Before we can identify the interactions among these components of the system and effe...

The Lake Malaŵi genus Melanochromis included five species at its inception and was originally distinguished from Pseudotropheus on the basis of morphology, including the arrangement of teeth on the lower pharyngeal bone. Thediagnosis has been extended twice, first to include all elongate mbuna that possess horizontal stripes and U-shaped toothbands and later to exclude mbuna that do not exhibit a sex-related reversal in their colour pattern. Recently, the diagnosisof the genus was refined on the basis of the melanin pattern. The genus now includes only species with a basic melaninpattern, which consists of two black horizontal lateral stripes on a light background. Most adult members of the genus,thus defined, have a sex-related reversal of pigmentation pattern. Here we describe Melanochromis mpoto n. sp. from thenorthwestern part of Lake Malawi, synonymize M. parallelus Burgess & Axelrod 1976 with M. loriae Johnson 1975,redescribe M. chipokae Johnson 1975 and M. robustus Johnson 1985, and reclassify and designate a lectotype for M. brevis Trewavas, 1935.

The Lake Malaŵi genus Melanochromis included five species at its inception and was originally distinguished from Pseudotropheus on the basis of morphology including the arrangement of pharyngeal teeth. The diagnosis has been extended twice, first to include all elongate mbuna that possess horizontal stripes and U-shaped tooth bands and later to exclude mbuna that do not exhibit a sex-related reversal in their color pattern. We have further refined the diagnosis of the genus on the basis of the melanin pattern, resolved a longstanding dispute regarding the validity of M. heterochromis, re-evaluated the status of M. vermivorus, synonymized M. mellitus Johnson 1976 with M. melanopterus Trewavas 1935, moved M. benetos Bowers and Stauffer 1977 to Pseudotropheus, and described M. kaskazini, M. wochepa, and M. mossambiquensis from the eastern shore of the lake. Melanochromis is still paraphyletic as two species, M. joanjohnsonae Johnson 1974 and M. labrosus Trewavas 1935, are not congruent with the rest of the group, but, currently, a better alternative for these two could not be found.