AC or DC? Two Newly Described Electric Fish from the Amazon Are Wired Differently

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HarleyK

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http://www.sciencedaily.com/releases/2013/08/130828103440.htm

http://www.pensoft.net/journals/zoo...efishes-gymnotiformes-hypopomidae-from-the-ce

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The two new species are bluntnose knifefish, genus Brachyhypopomus, that live under rafts of unrooted grasses and water hyacinth along the margins of the Amazon River called "floating meadows." These are weakly electric relatives of South America's famous electric "eel" (not a true eel) that can produce strong electric discharges of hundreds of volts. By contrast, these weakly fishes produce pulses of only a few hundred millivolts from an organ under the body that extends out onto a filamentous tail. Nearby objects in the water create distortions to the electric field that are sensed by receptor cells on the fishes' skin. In this way, they are able to "electrolocate" through their complex aquatic environment at night. Their short electric pulses, too weak to be sensed by touch, are also used to communicate the sender's species identity and gender to other electric fishes."The most striking differences between these two similar species have to do with their electric organs and their electric organ discharges, or EODs," says lead author John Sullivan, Curatorial Affiliate at the Cornell University Museum of Vertebrates. "If it weren't for these traits, we undoubtedly would have thought they were a single species. The one we are calling Brachyhypopomus bennetti has a huge electric organ, a short, fat tail, and produces a monophasic EOD; the other one that we're calling Brachyhypopomus walteri has a more typical electric organ, a long thin tail, and a more typical biphasic EOD."

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Amazing that they look so similar yet are so different when it comes to their electric organs.
 
Another great thread. Thanks for posting, these are some truly fascinating fish.
 
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