The Cichlid Fishes of Lake Malawi, Africa

Abstract of Doctoral Dissertation

Erna Elfriede Bruwer
Rand Afrikaans University, Auckland Park, South Africa (now part of University of Johannesburg), 2003
Adviser: F.H. Van der Bank  

Biochemical and molecular genetic studies of the southern African catfish genus Synodontis Cuvier, 1816 (Teleostei, Mochokidae)  

Synodontis Cuvier, 1816 (Teleostei, Mochokidae) species are often extremely abundant in local fisheries catches over their entire distribution range. They are appreciated as food as well as popular aquarium fishes. However, some species are extremely difficult to identify due to the taxonomically unreliable nature of prominent morphological features. Establishing the correct identification is important and can have far-reaching consequences (e.g. in fisheries, conservation, stock assessment, and angling records may be compromised by misidentifying species due to the complicated nature of present identification keys). The systematic status of many southern African Synodontis species is poorly understood and their identification remains problematic. This study involves characterising the species of the genus Synodontis by comparative morphological and genetic studies due to the above-mentioned problems.

Extensive field studies have lead [sic] to a simplified identification key. This key excludes the detail character information included in the published key that masks the more reliable characteristics. Synodontis njassae, S. macrostigma, S. macrostoma, S. leopardinus, S. thamalakanensis, S. woosnami, S. vanderwaali, S. nigromaculatus and S. zambezensis were used in an allozyme study with Parauchenoglanis ngamensis as outgroup. Fixed allele mobility differences were obtained at eight of the 15 loci studied. The dendrograms grouped all species with convex humeral processes in one clade. The species with concave humeral processes also grouped together, but with poor resolution with DNA - sequence analysis.




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