The next iPhone was reportedly spotted on a San Francisco train. Above, a customer tries out the new iPhone 4 at Apple's store in the Ginza district of Tokyo. (Yuriko Nakao/Reuters)

According to the report, a California man saw an unusual smartphone on the train and snapped a couple pictures of it. Then, upon reading 9 to 5 Mac’s latest report on possible iPhone 5 cases, he realized the phone he saw would fit in those cases and sent his pictures to the Web site.

The site is careful to note that neither it nor the tipster has confirmation of anything apart from what he saw: a phone that’s flatter, thinner, more rounded and sporting a bigger screen than any iPhone Apple’s released to date. The tipster also said that phone appears to be curved or tapered with a black glass or plastic back.

If the tipster’s right, this certainly isn’t the first time that Apple’s let its phones out into the wild. Gizmodo famously drew back the curtain on Apple’s iPhone 4 after buying it from a guy who found a prototype in a bar.

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