In fn. 20 pg. 264 I mentioned that the form PRIMOɔENIA from Praeneste appears to use an inverted C to indicate a segment resulting from the palatalization of a velar. In reading Alfred M. Tozzer's, A Maya Grammar, I learned that some early Spanish works represented the Mayan glottalized affricate /tsʔ/ with inverted c, i.e. ɔ. In fact, this usage is found already in Juan Coronel's Arte en lengua de Maya (1620). Could this practice have been inspired by the conventional view that Claudius' symbol for /ps/was an antisigma, i.e. a reversed sigma? Coronel doesn't discuss the alphabet he uses. According to Oliver 1949:253, who incidentally—I take the liberty of saying on my blog—was a thoroughly despicable person, the shape of this Claudian letter as transmitted in the manuscripts of Priscian was approximately ɔc not ɔ, which was introduced by emendation of Buecheler. If this is correct then the early Spanish padres could not have been directly inspired by Claudius' practice. Oliver is certainly not correct in attributing the interpretation of antisigma as ɔ to Buecheler. It goes back at least to A. L. Schneider according to Fr. Osann, but how much beyond that I can't say.
Oliver, Revilo P. 1949. The Claudian letter Ⱶ, American Journal of Archaeology 53:249–57
Tozzer, Alfred M. 1921. A Maya Grammar. Cambridge MA: Peabody Museum