Scientists are highly confused by the discovery of a toothy subterranean catfish named "Kryptoglanis shajii."

According to LiveScience, the rare catfish only lives in the Western Ghats mountain range in Kerala, India and is rarely ever seen by humans. However, its strange skeletal structure is making it difficult for researchers to identify it.

"The more we looked at the skeleton, the stranger it got," John Lundberg, Drexel's resident fish zoologist and a professor in the university's School of Arts and Sciences, said in a press release. "The characteristics of this animal are just so different that we have a hard time fitting it into the family tree of catfishes."

Scientists had not made the fish a new species until 2011, but its skeletal structure is what makes it such a mystery. On the outside, Lundberg said the fish looks like a normal catfish, but it is missing several bony elements in its face and jaw.

"The characteristics of this animal are just so different that we have a hard time fitting it into the family tree of catfishes," Lundberg said.

The catfish's facial bone structure made its lower jaw protrude and the front end to compress, all in all similarly to the snout of a bulldog.

"In dogs that was the result of selective breeding. In Kryptoglanis, we don't know yet what in their natural evolution would have led to this modified shape," Lundberg said.

The scientists concluded the catfish, which is no bigger than a person's small finger, ate meat such as small invertebrates and insect larvae, based on its teeth and subterranean environment.

Not even another research team, who has a study published in the journal Ichthyological Exploration of Freshwaters, could determine Kryptoglanis' closest relative.

"There was an amazing congruence between the results," Lundberg said. "Neither of us was way out.

"It continues to be a puzzle."