The missing mainland link: scanning Late Messinian mammals to uncover the initial colonisers of the Balearic Islands, Spain.

Mallorca is isolated from the mainland for 5.3 million years, resulting in unique adaptations within the endemic fauna. We recently uncovered continental deposits on the island dating back to just before this prolonged period of isolation, including a dolostone containing multiple vertebrate fossils. This is the first and perhaps only direct evidence of the initial colonisers of Mallorca, and a thorough analysis of this sample can be groundbreaking. However, the encasing dolostone is too hard for extracting the delicate fossil material physically, whilst the density, weight and size of the block restricts the use of traditional µCT scanning techniques. Using the scanning facilities at ESRF, we aim to uncover and digitally segment the fossils from its matrix. The details of this fossil-bearing rock will unveil new insights of initial colonisers, before the onset of drastic adaptations, and can represent a paradigm-shift in our understanding of evolutionary mechanisms on islands.