This paper reports on a corpus of Brazilian Portuguese (BP) mandible movements. The data was collected using a recently available technique, the MARRYS helmet, which allows for quick and reliable collection of mandible data of a large number of speakers. Audio and mandible were recorded from more than 90 L1 and L2 BP speakers. The recording process and signal synchronization are presented. A partial set of the corpus, based on 37 L1 speakers producing three sentences mostly composed of /a/ vowels, was segmented at the phone level. The jaw movements are compared to the sentence's prosodic structure. Results indicate that, similar to other languages, Brazilian Portuguese speakers show increased mandible lowering for stressed syllables but also quick mandible closing. Some interesting mandible opening and closing patterns are also reported on the prestress or post-stress positions in relation to the prosodic structure of Brazilian Portuguese.