In a Ray Charles talented fashion a blind cave fish (settle down, just the blind and talented part) in Thailand has gone a long ways to explaining that move from primordial ooze to upright to scientists in a recent study.
Waterfall climbing fish
Tetrapods, or early land vertebrates, worked out how to walk on terra firma owing to a pelvis that fused hind legs to spine and developed interlocking flanges in the vertebrae to facilitate overcoming that pesky gravity.
Essentially, these amazing fish began to walk like salamanders with their fore and hind legs working in a tandem cycle while moving their trunks to walk. And then, just to show off, they climbed waterfalls.
“It’s really weird,” said John R. Hutchinson, a biologist at the Royal Veterinary College at the University of London who spoke to the new study with the New York Times. “It’s a good example of how much fish diversity there’s left to be discovered.”
Dr. Hutchinson’s was not involved in the study but he has more credibility than I and was left saying “weird” just as I was this morning.
Just another reason to go to Thailand
The researchers involved in the study that was published last Thursday in the journal Scientific Reports genuinely sound aghast even today with their find.
Many fish have figured out ways to deal with being a “fish out of water” but nothing like this.
For example, frogfish have managed coral reefs by using their fins like legs but only underwater. Mudskippers can use their fins like canes and enjoy a limited amount of freedom on land. Perhaps most fascinating outside of the recent Thai cave find is the Hawaiian Nopili rock-climbing goby which uses its mouth as a suction cup in order to climb rocks.
But, the waterfall-climbing, blind, two-inch cave critter outdoes each with its unique salamander-like gait.
Discovered in 1985, it’s truly impressive and was recently filmed by Apinun Suvarnaraksha, a biologist at Maejo University in Thailand, and Daphne Soares, of the New Jersey Institute of Technology.
Soares recently brought her video to the attention of a colleague, Dr. Brooke E. Flammang, a biomechanics expert and the video impressed.
“I was completely blown away,” Dr. Flammang said. Instead of flopping or crutching, the cave fish were using what looked like a full-blown tetrapod gait.
“These guys seemed to be very leisurely walking up the rock face,” Dr. Flammang said.
The species in question is protected and, well, only found in caves in Northern Thailand so Flammang was unable to study the creature in a lab setting.
However, Dr. Suvarnaraksha was able to help Flammang by taking a preserved specimen of the fish to a dental school for CT scanning and shared the images with her.
Generally speaking, fish pelvises (Never thought I would write those words) are simply floating bones that guide the pelvic fin for stability or simply to keep fish from spinning while swimming in a barrage of barrel-rolls. But this climbing fish has a pelvis more human than fish with elongated ribs fused to a number of pelvic bones that allows for hind leg “walking.”
Flamming is of the opinion that with further study, we’re looking at an understanding of how fish left the water, and that’s a missing chapter in evolution.