But this cavefish does far more than those fish do, as it is able to actually climb up waterfalls in a similar fashion to a salamander.
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Waterfall-climbing cavefish Cryptotora thamicola uses unusual pelvic adaptations to walk over slippery rocks and through fast-flowing water.
Cryptotora thamicola, as the species is known, is not the first fish scientists have discovered that can move outside of water. A team of researchers from the New Jersey Institute of Technology (NJIT) travelled to Thailand to study the Cryptotora thamolica, a species of blind fish found in a handful of caves.
“The pelvis and vertebral column of this fish allow it to support its body weight against gravity and provide large sites for muscle attachment for walking”, Flammang said.
Ultimately, Flammang says the research gives information about how adaptable the structure of the fish body is and how these features come close to the previously discovered evolution of tetrapods. But the conditions it thrives in would put off most fish, as it subsists on a diet of microbes that live on the vertical walls of its underground caverns. Study results show that the fish uses its fins and even its pelvis to help them walk on land.
Although scientists are not calling the fish a missing link, they believe it may provide clues about how animals made the transition from sea to land. This is the 1st fish that as a living species acts in a similar way as it must have acted when it evolved to a terrestrial environment from a fluid environment.
“When you define what a tetrapod is, one of the characteristics that you use is these interlocking supports among the vertebrae to support their body weight against gravity”, Flammang said, “As well as having a robust pelvis so that it can transfer forces from the body toward the ground without crumpling”.
Dr. Flammang and co-authors published a paper in the journal Scientific Reports this week. Polypterus8, mudskippers9,10 and walking catfish11 move on land via crutching or lateral pushing by the posterior body and tail to rotate forward over their pectoral fins.
The cavefish was first described in 1985, but the recent study sheds new light on its morphology and how this enables it to walk.
Furthermore, Cryptotora thamicola has large anterior and posterior zygapophyses, transverse processes, and broad neural spines in the vertebral column of its sacral area – features that are all closely associated with terrestrial organisms, the study authors wrote.
“From an evolutionary perspective, this is a huge finding”.
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Citation: “Tetrapod-like pelvic girdle in a walking cavefish”, Brooke E. Flammang, Apinun Suvarnaraksha, Julie Markiewicz & Daphne Soares.
