New to nature No 120: Akawaio penak

An electric eel-like fish that can swim backwards as well as forwardsSouth American or gymnotiform knifefishes include about 150 species occurring throughout the humid Neotropics, from Panama south to northern Argentina. With the exception of Chile, gymnotiforms are found in every country on the South American continent. Lacking pelvic and dorsal fins, these fish have narrow bodies and tapered tails with greatly elongated anal fins. In motion, the body is held rigid with waves rippling down the anal fin propelling the fish. This undulating source of locomotion enables knifefish to swim as effortlessly backwards as forwards. South American knifefishes are varied in size, from under four inches to more than a foot in length.Within this large range are remote and poorly-known drainage systems that remain nearly completely unexplored. One is found in Guyana. The Mazaruni river runs through the eastern expanse of the Guiana Shield escarpment. The upper reaches of the Mazaruni are separated from the lower by waterfalls that constitute a barrier to fish movements. Only in the past few years have ichthyologists begun systematic collecting of the fish fauna of the upper Mazaruni.Joint expeditions by the Royal Ontario Museum and the University of Guyana have, since 2008, turned up three genera and 11 species new to science. To date, the new species include cichlids, characiformes, armoured catfishes, and, now, electric knifefish. Electric organs in fish have been known since the 1770s ...
Source: Guardian Unlimited Science - Category: Science Authors: Tags: Americas World news Features Animals The Observer Zoology Environment Guyana Science Wildlife Source Type: news