Researchers have spotted individuals of a species of catfish, the Chaetostoma microps, climbing a nearly vertical flowstone waterfall in a cave system. The findings have been published in the journal Subterranean Biology.
A group of international researchers stumbled upon a peculiar and spectacular discovery when they set out to make an inventory of the flora and fauna living in a cave found in Tena, Ecuador: they spotted catfish climbing up a somewhat vertical flowstone waterfall. Some of the catfish had even reached heights of 3 meters.
This event marks the first documented case where individuals of the armoured catfish species – Chaetostoma microps – have been seen foraying out of the water, and that too, in a cave. The Chaetostoma microps, endemic to Ecuador and Peru, usually lives in the Amazon. It is known to feed on algae – why would it be found in a cave then? The authors of the paper have speculated that they might have passed through the cave system without actually living there, or they might have been grazing on microbes found in the cave streams.
While the C. microps is known to attach to rocks and trees in rivers, some of its relatives are known to climb over rapids when spawning. For instance, the Loricariidae, another member of the armoured catfish family, are able to cling to the surface of the water while breathing and scraping off algae at the same time. Seeing the C. microps climb was therefore not much of a surprise to the researchers. But, finding them in a cave seems to have caught the their special attention.
One of the researchers, Geoff Hoese, said that the specimens found in the cave might be physically different from those which normally live above ground.
“There isn’t enough data at this point to do more than speculate, but it’s nice to think that we may be watching a small but significant evolutionary step as a species moves from one niche to another,” Hoese told BBC Earth.
The cave catfish. Photo credits: Geoff Hoese/ Subterranean Biology.