Nintendo doesn't know when the new Golden Sun game is coming out on "the Nintendo DS family of systems."
Nintendo's release date-filled press release yesterday was missing a rather important DS title: Golden Sun: Dark Dawn. According to a Nintendo representative, The company has "not yet determined a specific launch date for Golden Sun: Dark Dawn for the Nintendo DS family of systems."
It is very likely that Golden Sun: Dark Dawn will not be coming out in the next three months, which were laid out without many gaps yesterday, but that doesn't rule out a December release. It is more likely that Dark Dawn has been pushed back to 2011, though, and due to the wordage of "the Nintendo DS family of systems," it could even have 3DS support.
UPDATE 8/19 - Nintendo has clarified that "the Nintendo DS family of systems" refers only to products currently on the market, so the mystery and speculation behind the phrase is explained.