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.
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.
Courtesy of NJIT
Scientists at the New Jersey Institute of Technology have found a blind, but surprisingly mobile, cavefish in Thailand.
Other fish can 鈥渨alk,鈥� but none are quite like the blind聽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鈥檛 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 , researchers report in a paper published Thursday in the open-access journal Nature Scientific Reports.
鈥淚t possesses morphological features that have ,鈥� said study co-author Brooke Flammang, an ichthyologist at Harvard University's Museum of Comparative Zoology, in a press release. 鈥淭he 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鈥檚 pelvic girdle allows it to move with a side to side motion like a salamander, or what researchers describe in the study as a 鈥渟tanding wave.鈥� 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 鈥渢rackways鈥� 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.
鈥淭his 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,鈥� said Dr. Flammang.