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Let XD be the Shimura curve associated with an indefinite rational quaternion algebra of discriminant D, and let p be a prime dividing D. In their investigations on the arithmetic of XD, Jordan and Skorobogatov introduced a covering XD,p of XD whose maximal étale quotient is referred to as the Shimura covering of XD at p. The goal of this note is to describe the group of modular automorphisms of the...