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Electric Fish
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Evolution of Electric Fish
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The African mormyrids and South American gymnotids appear to have no common
ancestors, yet have developed remarkable similarities through convergent
evolution.
Most of the common phylogenetic relationships are in morphological characteristics;
however, relationships have also been shown on the physioloical and molecular levels.
The gymnotids have been shown to be a sister group to a family of electroreceptive
catfish (Alves-Gomes, et al. 1995). The electrorecptive ability of the
catfish allows them to percieve the low frequency of pulse type weakly
electric fish. It has been hypothesized that the South American hummers
may have evolved from the clickers because the catfish can not detect the
hummer's higher frequency EOD's (Hagedorn, unpublished). Many hummers have
also evolved a neuronally-derived electric organ in place of the more
primitive myogenic organ, allowing them to further increase the frequency
of EOD emmision.
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