Friday 14 September 2012

A new species of Cichlid Fish from Lake Malaŵi.

The Cichlids are an extremely successful group of freshwater Perciform Fish (Perches), found in North, Central and South America, as well as the Caribbean, the Middle East, South Asia and, most notably Africa, where the group reaches its highest diversity. Over 700 species have been described from Lake Malaŵi alone, which is more species of freshwater fish than have been described from the entire Northern Hemisphere and slightly over 1% of every vertebrate species ever described. 

In a paper published in the journal Zootaxa on 6 August 2012, researcher and Cichlid specialist Michael Oliver describes a new species of Cichlid from Lake Malaŵi. The new species is based upon two specimens in museum collections; the first caught in an experimental sampling expedition, north of Thumbi Island West at a depth of 17-38 m, in 1980, and now sits in the collection of the Peabody Museum of Natural History at Yale University, and the second purchased from indigenous fishermen at Nkhata Bay in 1997, and now in the collection of the Royal Museum for Central Africa in Tervuren, Belgium. Since the Cichlid fauna of Lake Malaŵi has been studied and sampled extensively for many years and only two specimens of this fish are known it is presumed to be quite rare.

Map of Lake Malaŵi, showing the locations where the two specimens were found. Oliver (2012).

The new Cichlid is placed in the genus Hemitaeniochromis, which until now contained only a single species (Hemitaeniochromis urotaenia), and is given the name Hemitaeniochromis brachyrhynchus, the short-snouted HemitaeniochromisHemitaeniochromis brachyrhynchus has a shorter snout than Hemitaeniochromis urotaenia, caused by a narrowing of the lacrimal bones (which form part of the eye socket); this also causes larger eyes in Hemitaeniochromis brachyrhynchus. The colouration of Hemitaeniochromis brachyrhynchus is unkown, as both preserved specimens have lost their original colour.

The Yale specimen (a) and Royal Museum specimen (b) of Hemitaeniochromis brachyrhynchus. (a) is 123.6 mm long and (b) is 81.5 mm long. Oliver (2012).
The closely related Hemitaeniochromis urotaenia. Oliver (2012).

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