Pollimyrus castelnaui, a mormyrid
found in Lake Malawi; illustration from Skelton (1993), used by permission
of P.H. Skelton
Pollimyrus castelnaui has been given the colorful name "Dwarf stonebasher" (from its feeding motions, I suspect) among English-speaking southern Africans. This is indeed the smallest mormyrid known from Lake Malawi, reaching only 7 cm (2¾ inches) in standard length (without caudal fin). It is distributed from the Cunene River on Africa's Atlantic coast eastward to Tanzania. I include the species in this listing because Skelton (1993) states that it is "...found in northern areas of Lake Malawi." No details of the lakeshore localities are available in Skelton or in FishBase.

Except for its usual habitat, "dense vegetation along margins of rivers and floodplain lagoons" (Skelton), nothing is known of its biology.

Pollimyrus castelnaui was classified in the genus Marcusenius until 1971. Around Lake Malawi it is most likely to be confused with Petrocephalus catostoma, but P. castelnaui is the only mormyrid in the area to share all of the following characteristics (adapted from Skelton, 1993: 92-93):

  1. Length of dorsal fin base shorter than anal fin base;
  2. Chin without a swelling;
  3. Mouth small and subterminal (located only slightly below the middle of front of head); and
  4. Anterior and posterior nares (nostrils) on each side of head are separated by more than the diameter of each.

The above painting by Elizabeth Tarr is copyright © by the South African Institute for Aquatic Biodiversity (formerly known as the J.L.B. Smith Institute of Ichthyology). It is reproduced here from Skelton (1993) with the kind permission of Prof. P.H. Skelton.

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The Cichlid Fishes of Lake Malawi, Africa:  MalawiCichlids.com

Last Update: 13 October 2000
Web Author: M. K. Oliver, Ph.D.
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