Study suggests at least 11 fish species are capable of walking
An international team of scientists has identified at least 11 species of fish suspected to have land-walking abilities. The findings are based on CT scans and a new evolutionary map of the hillstream loach family, which includes the only living fish species caught in the act of walking: a rare, blind cavefish known as Cryptotora thamicola, or the cave angel fish. Pinpointing which species of hillstream loaches have walking capabilities can help scientists piece together how the first land-walking vertebrates might have come to be. The research was funded in part by the U.S. National Science Foundation.
Credit: National Science Foundation/Karson Productions
Fish out of water.
I'm Bob Karson with the Discovery Files, from the National Science Foundation.
Ever imagine the first ancient underwater creatures that emerged and walked on land? (Sound effect: cartoon fish voice) "Ok, I'm swimming, climbing, pulling, dragging, walking. Walking? (Sound effect: car horns) Hey I'm walkin' here!"
The quest to piece together that epic evolutionary step when land-walking vertebrates first appeared, is getting some help from U.S. and Thai scientists who’ve identified at least 11 species of fish suspected to have or have had land-walking abilities. (Sound effect: cave sounds) (Sound effect: reverb) Right now, there is only one living species of fish that's been observed walking: a Loach called the Cave Angel Fish -- a rare, blind cave-stream-dweller whose pelvis more closely resembles an amphibian's. An adaptation that lets it grip rocky streambeds, even climb waterfalls.
The team used CT scans to study the bone structure of some 30 Loach species. The eleven that were good candidates for walking all had an unusually hefty pelvic girdle and, unlike most fish, bone that connects the spine to the pelvic fin. With DNA analysis, the team used hundreds of genes to trace how pelvic shapes in these fish evolved over time.
A greatly improved understanding of the evolution of an extremely uncommon event -- (Sound effect: cartoon fish) "heads up -- comin through!" -- the ability of a fish to walk on land. (Sound effect: cartoon fish) "Anybody see my step counter?"
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