This claim appears to be based on Title 31 of the Laws of Puerto Rico, section 1401 et seq. Section 1401 states: "The author or beneficiary of a literary, scientific, artistic and/or musical work has the right to benefit from it, and the exclusive prerogatives to attribute to him/herself or retract its authorship, dispose of his/her work, authorize its publication and protect its integrity, in accordance with the special laws in effect on the matter".
Title 31 continues...the moral right has a 50 year duration (1401c); and, does not attach to works created for advertising entities or for promoting goods or services, unless otherwise agreed (1401e). The moral right includes a right to resale royalties, totalling 5% deducted from the seller's earnings (1401h). Remedies for infringement include temporary or permanent injunction, restitution, seizure, or destruction of the infringing works (1401f).
Notably, Puerto Rico provides a moral right specifically for musical works (1401i), which requires the complete name of the composer of a musical work and corresponding song shall be specified and mentioned, in addition to the complete name of the artist or performer, on the production, recording, show or musical event at issue. This section should come into play in the Pascual suit filed yesterday.