The members of the genus Synodontis, commonly known as the squeaker catfishes of Lake Tanganyika, evolved from a single common ancestor according to a paper* published in a recent issue of the Journal of Evolutionary Biology.

synodontis catfish

Researchers Day, Bills and Friel** analysed 1697 base-pair sequences consisting of nuclear (ribosomal protein-codin gene S7), mitochondrial (cytochrome b) and transfer RNA gene fragments in 65 samples (representing about 40 species) of squeaker catfishes to study the evolutionary relationships of the group.

Through their research, the authors were able to track down a single origin for the Lake Tanganyika species flock. The members of the genus Synodontis all evolved within the last 5.5 million years which makes them a comparatively new addition to this Great Rift Valley Lake which is believed to be at least 9 million, perhaps even 12 million, years old.

Day, Bills and Friel also recovered a monophyletic group of southern African riverine species which seems to have diversified very rapidly (during the last 890,000 years). This group was believed to have been formed due to adaptive radiation within Lake Makgadikgadi; a lake which is now extinct.

* Day, JJ, R Bills & JP Friel (2009) Lacustrine radiations in African Synodontis catfish. Journal of Evolutionary Biology 22, pp. 805–817.

**Julia Day, Roger Bills and John Friel