In their quest to look for a rare whale, a group of researchers believes they have instead discovered a previously unknown species off the western coast of Mexico. Even though DNA testing hasn’t been confirmed yet, they’re very confident.

The researchers, working with the Sea Shepherd Conservation Society, were on board a vessel on November 17 when they observed three beaked whales surfacing in nearby water. The sighting happened 100 miles north of the San Benito Islands, a group of remote islands located 300 miles from the US border.

The expedition’s focus was the study of cetaceans in the waters surrounding the islands, and researchers were particularly hoping to identify a beaked whale species associated with an unidentified acoustic signal. They took photographs and video recordings of the animals and used a microphone to record the acoustic signals.

The beaked whale experts said they are “highly confident” that the photographic and acoustic evidence will reveal the presence of an entirely new whale species. They have already started analyzing the environmental genetic sampling, which they believe will prove the existence of this new species of whale.

“We saw something new. Something that was not expected in this area, something that doesn’t match, either visually or acoustically, anything that is known to exist,” said Dr. Jay Barlow, who was part of the expedition, in a statement. “It just sends chills up and down my spine when I think that we might have accomplished this.”

Back in 2018, scientists recorded an unknown acoustic signal in the waters north of the San Benito Islands. The signal was believed to have been the sound of a species called Perrin’s beaked whale, which is one of 23 known species of beaked whales found in oceans around the world. Still, there have been no live sightings of it.

The animal documented is indeed a beaked whale, but it’s not Perrin’s beaked whale or any other known species, according to the researchers. Initial analysis by the team from Sea Shepherd showed that the physical characteristics and the acoustic recording of the sighted whales don’t match known species of beaked whales.

Perrin’s beaked whale has teeth at the end of the jaw, while in the one the team spotted the teeth were further back. Similar differences were seen regarding their sizes and color patterns. “it really didn’t seem to match any of the other characteristics of described beaked whales,” said Elizabeth Henderson, one of the researchers.

Takashi Fritz Matsuishi, a professor at Hokkaido University’s School of Fisheries Sciences and co-author of a 2019 paper identifying another new species of beaked whale, told Mongabay it’s possible the researchers might have found a new species. But he warned it can’t be identified by DNA analysis or visual observations.

“The external morphology and osteological descriptions are strictly required,” Matsuishi said, referring to the animal’s physical features and skeletal structure. “That is the reason that our Sato’s beaked whale [took] 6 years to be described as a new species since the publication of the paper showing the genetical difference in 2013.”

While they wait for the DNA analysis, the researchers are currently working on a paper to describe the species’ acoustics and morphological characteristics, which they hope to release shortly.