Shared understandings are important for software development as they guide effective individual contributions and coordination of the software development process. However, it is not clear if such understandings can be developed in highly distributed groups that do not regularly meet face-to-face. In this paper, we present the results of a preliminary analysis of shared mental models within a Free/Libre Open Source Software (FLOSS) development team. We analyzed mental models using cognitive mapping and process analysis and compared the models of four developers from the Apache Lucene Java project. Our analysis suggests that there is a high level of sharing among core developers but the sharing is not complete, with some differences related to tenure and role in the project. Finally, we suggest directions for further research on shared mental models in FLOSS teams.