Cover image:

Thin section under petrographic microscope of fossil remains of the rebbachisaurid sauropod Katepensaurus goicoecheai of Bajo Barreal Formation (Upper Cretaceous, Argentina). Part of a permineralized vascular canal is observed, including a first layer of hematite, a second layer of silica as chalcedony and quartz, and a third layer in the center that fills completely the canal with zeolites (crossed nicols). See Casal et al. (2017) in this issue.