The Rolling Stones’ famed “tongue and lips” logo is at the center of a new federal lawsuit, launched by a small clothing chain that says it was unfairly threatened by Universal Music Group’s Bravado merch company with “unfounded” infringement litigation over a similar logo.

In a lawsuit filed Wednesday (March 29), apparel retailer Simply Southern claimed it had received a cease-and-desist letter from Bravado, a unit of UMG that sells licensed merchandise for the Stones and dozens of other major artists. The letter allegedly took aim at T-shirts that featured a “disembodied mouth,” claiming they were confusingly similar to the iconic logo.

But lawyers for Simply Southern say its apparel designs were “clearly and demonstrably different,” and they want a federal judge to rule that the company “has not infringed Bravado’s asserted intellectual property rights.”

“Simply Southern’s mouth images show many elements that are very different from Bravado’s asserted tongue/lips image,” the company wrote in its complaint. “For example, Simply Southern’s images have a more plump lower lip, more square teeth, and a wider and more open mouth when compared to Bravado’s asserted image.”

A representative for Bravado declined to comment. The Rolling Stones themselves are not named in the lawsuit and are not accused of any wrongdoing; a rep for the band did not respond to a request for comment on the situation.

Called “the most famous logo in rock ’n’ roll” by the New York Times, the “tongue and lips” image was created in 1970 by John Pasche, a London art student who had been commissioned by the band to create a poster for its upcoming European tour. The design was then tweaked slightly by designer Craig Braun before it appeared in its final version on the back cover of the band’s 1971 album Sticky Fingers.

Since then, the Stones logo has appeared countless times — on music releases, T-shirts, stickers, posters and even as the stage for the band’s halftime performance during Super Bowl XL.

According to Wednesday’s lawsuit, Bravado sent Simply Southern a letter on March 1, claiming to be the exclusive licensee to sell Rolling Stones merchandise. The lawyers for Bravado warned Simply Southern that its products were “confusingly similar” to the tongue and lips design, and that such offending merchandise infringed the band’s trademarks.

The complaint filed in federal court (available in its entirety here) includes images Simply Southern’s two offending logos. Both appear visually similar to the Stones logo, but with differences. One is highly similar in shape, but features a different pink-and-leopard print color scheme; the other features the same red color scheme as the Stones logo, but includes a different orientation with different tongue placement.

From Simply Southern’s perspective, that’s enough difference to avoid liability for trademark infringement.

“Because the mouth is an inherently expressive body part, subtle changes in shape and positioning result in markedly different interpretations of emotional expression,” the company wrote. “Bravado’s asserted image is mostly devoid of emotion but has slight hints of either playfulness or defiance. By contrast, Simply Southern’s images are deeply expressive.”

Read Simply Southern’s full complaint here: