Bizarre cavefish can walk like a four-legged land-dwelling creature

The discovery of the bizarre cavefish in Thailand could help scientists better understand the evolution of land-walking animals.

Courtesy of NJIT
Scientists recently discovered a blind, walking cavefish, Cryptotora thamicola, in Thailand that has similar anatomy to early four-legged creatures, according to a paper published Thursday in the journal Nature Scientific Reports.

Scientists at the New Jersey Institute of Technology have found a blind, but surprisingly mobile, cavefish in Thailand.

Other fish can “walk,” but none are quite like the blind Cryptotora thamicola. This fish is the only one of its kind that can walk and climb fast moving waterfalls, almost like a salamander.

These energetic little climbers don’t move like other fish, even fish that have developed the ability to walk on land. Instead, these walking cavefish have developed tetrapod-like features that allow them to move like those early landwalkers, which first developed the ability to move on land about 420 million years ago.

Tetrapods were the earliest four-limbed creatures to walk on land. Their features that allowed them to walk instead of swim included stiff spines made by interlocking vertebrae and the growth of pelvises to allow them to walk.

The walking cavefish have many of the same features as early tetrapods, researchers report in a paper published Thursday in the open-access journal Nature Scientific Reports.

“It possesses morphological features that have previously only been attributed to tetrapods,” said study co-author Brooke Flammang, an ichthyologist at Harvard University's Museum of Comparative Zoology, in a press release. “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."

The cavefish’s pelvic girdle allows it to move with a side to side motion like a salamander, or what researchers describe in the study as a “standing wave.” Other fish move with the familiar undulating, or swaying, motion.

Although researchers just published their paper this week, the walking cavefish was discovered in 1985. The walking cavefish is native to caves in Thailand, and is considered a rare species.

Because the species is protected, researchers studied it by visiting the cave, taking video, and examining preserved specimens in Thai museums.

Scientists have found “trackways” made by dragging tetrapod fins in European caves that date back about 400 million years, but the earliest skeletal evidence they have of the creatures is from 375 million years ago.

Researchers are particularly intrigued by the walking cavefish because it offers a window into the evolution of four-legged creatures like the tetrapod.

“This research gives us insight into the plasticity of the fish body plan and the convergent morphological features that were seen in the evolution of tetrapods,” said Dr. Flammang.

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to