I'm kind of weirded out by this story about the possibility of a new great ape species in Congo. This is the kind of thing you are likely to find in a Victorian adventure novel. A report will be published next week in The New Scientist. That makes me suspicious, why won't a peer reviewed journal publish this? The evidence is way too sketchy to come to any conclusion, but perhaps the scientists wanted to stake their claim to discovery before others beat them to the punch so they decided to go the route of sensationalism. Here are some options:

• New species.
  
• A population that derives from chimp-gorilla hybridization.
  
• A form of chimp.
  

I would bet on the last, though the first would be a really exciting option (it seems like they could have gotten genetic material from the nests of these animals). Remember, the distinction between Bonobos and Common Chimpanzees is pretty recent. This is a pretty creepy anecdote:

She describes her encounter with them: "Four suddenly came rushing out of the bush towards me," she told New Scientist.

"If this had been a bluff charge, they would have been screaming to intimidate us. These guys were quiet. And they were huge. They were coming in for the kill. I was directly in front of them, and as soon as they saw my face, they stopped and disappeared."

In the Sundarbans on the border of India and Bangladesh men will wear face-masks on the back of their heads because tigers generally do not like to attack head on. This story seems to echo shades of the movie Congo. I would have been rather weirded out by the discovery of new large mammals in the 21st century (most of these sorts of discoveries recently have been in the region of southern Laos and the Annamese highlands in Vietnam), but a great ape?!?! Extraordinary claims demand extraordinary evidence.

Related: Jason Malloy's post on this topic from a year back (it has pictures!). Jason notes the mtDNA seems to be chimpish.

Addendum: From The Telegraph:

Dr Andrew Whitten, of St Andrews University, questioned whether behavioural differences were enough to suggest a new ape. "There are huge cultural differences among chimpanzees," he said.

"I do not think that behaviour makes a good marker for sub-species in great apes as flexible as chimps."

Of course there seem to be great morphological differences too. But the same could be said of humans. I want to see the coalescent times for this ape's genes with the Common Chimpanzee and Bonobos. But these semantic issues highlight some of the problems with defining "species."