Abstract
Building reliable palaeogeographical maps of the Carboniferous period is a complex effort due to the active tectonics of the Variscan Orogeny. For the western Palaeotethys, which was directly affected by it, numerous maps have been proposed based on tectonic, palaeomagnetic, and sedimentologic data. This paper presents a detailed palaeobiogeographical analysis of the late Visean based on the distribution of rugose corals. The late Visean presents high rugose coral diversity in the Western Palaeotethys, driven by a significant transgression and the warm climate conditions of the period. Our rugose coral data base spans from Nova Scotia to the Moscow Basin and from the Sahara to central Europe. We analysed this data using Simpson and Dice indices. The analysis revealed distinct patterns of similarity. The British areas are closely related. NW Spain and North Morocco are most similar to each other, but also share substantial faunal similarities with Belgium and the Sahara. Germany and Poland are grouped together but show different relationships with other areas. Türkiye has a distinct fauna to the other regions, and the Balkans low diversity and lack of recent studies complicate comparisons. Despite limitations arising from uneven fossil records, these findings provide a nuanced understanding of Visean rugose coral distribution and biogeographic relationships in the western Palaeotethys.