Hey! Pikmin, the series' upcoming 3DS spin-off, is not being developed by Nintendo.

Instead the game is being made by Arzest, the studio behind poorly-received 3DS side-scroller Yoshi's New Island.

More recently, Arzest made the 3DS version of Mario & Sonic at the Rio 2016 Olympic Games, and worked on a couple of mobile games.

Pikmin fans have reacted in surprise to this news, which was revealed today by the Australian Ratings Board.

Prior to today, Hey! Pikmin was widely expected to be an internal Nintendo project, as Pikmin 1, 2 and 3 were. Indeed, that trilogy was overseen by legendary Nintendo developer Shigeru Miyamoto - something Yoshi's New Island certainly wasn't.

"If it were a toy, you'd make sure you kept the receipt," Chris Schilling wrote of Yoshi's New Island upon its release in 2014. Ouch.

Some fans had assumed Hey! Pikmin was the "Pikmin 4" which Miyamoto confirmed to Eurogamer back in 2015. "We can confirm that Pikmin 4 is in development but that is all we can confirm at present," Nintendo told me at the time.

Miyamoto did not disclose which console Pikmin 4 would actually launch on, but he had at this point already talked of plans for another Wii U Pikmin project - one which would help sell that console. But as the Wii U's hardware fortunes faltered, this project appeared to have been put on ice.

In short, it now seems unlikely Miyamoto was talking about Hey! Pikmin, a game designed specifically for 3DS by a studio which Miyamoto does not oversee. And that means, hopefully, a proper Pikmin 4 is still around the corner - for Nintendo Switch.