The scientists at the New Jersey Institute of Technology have found a blind cave fish that can walk like a four-legged land creature in Thailand. It can walk and climb on waterfalls like a salamander.
The blind cave fish is called the Cryptotora thamicola and it moves unlike any other fish that "walks" on land. It instead has developed tetrapod-like features that allow them to move like the early landwalkers, which developed the ability about 420 million years ago.
The tetrapods were the earliest four-limbed creatures to walk on land. They had features that allowed them to walk like stiff spines and the growth of pelvises. The walking, blind cave fish have many of the same features as the early tetrapods, according to a report in Nature.
The cave fish eats microbes and organic matter that grows on the cave walls it inhabits. In 1985, it was discovered deep inside a system of caves in northern Thailand and cannot be found anywhere else, according to a report by the IUCN Red List. Since it is protected, the researchers can study it by visiting the cave, take videos and examine preserved specimens in Thai museums only.
Brooke Flammang, an ichthyologist at Harvard University's Museum of Comparative Zoology, said in a press release that the cave fish possesses morphological features that have previously only been connected to tetrapods. It has a pelvis and vertebral column that allows it to support its body weight against gravity and provide large areas for muscle attachment for walking, he added.
The pelvic girdle of this cave fish allowed it to move with a side to side motion like a salamander or what the researchers involved in this research describe as a "standing wave." Some other fish would move with the familiar swaying motion.
In the past, some scientists have found "trackways" made by dragging tetrapod fins in European caves that can be traced back to about 400 million years. Due to this discovery, researchers are now interested by the walking cave fish because it offers more insight into the evolution of the four-legged creatures like the tetrapod.
Check out the cave fish video below: