Synchrotron X-ray micro Computed Tomography of a fossil caridean shrimp MNHN.F.A58277 from the La Voulte-sur-Rhône Konservat-Lagerstätte (ca. 165 Ma)

The specimen MNHN.F.A58277 is housed in the palaeontological collections of Muséum national d’Histoire naturelle, Paris. It corresponds to a caridean shrimp preserved within a sideritic nodule from the Callovian (Middle Jurassic, ca 165 Ma) La Voulte-sur-Rhône Konservat-Lagerstätte. The specimen was historically mechanically prepared to reveal its dorsal side., the appendages remaining inside the nodule.
The dataset presented here result from the acquisition performed at the BM18 beamline of the European Synchrotron Radiation Facility (Grenoble, France) using propagation phase contrast synchrotron X-ray micro-computed tomography. The acquisition comprise most of the nodule in which the specimen is enclosed. The beamline was setup for filtered white beam using the 1.56 T central pole of the tri-pole wiggler, with 0.44 mm of Molybdenum, 15 mm of SiO2, 59.3 mm of glassy carbon and 7.5 mm of Sapphire, resulting in a total integrated detected energy of 96.7 keV. The sample detector distance was set to 4 m. The indirect detector comprised a LuAG:Ce 250 µm scintillator, visible light lenses set for 1x magnification, and an Iris 15 sCMOS camera (Teledyne Photometrics, Tucson, AZ, USA), resulting in a measured isotropic pixel size of 4.007 µm. The usable field of view was (vertical x horizontal): 1856 x 4944 pixels, corresponding to 7.424 x 19.776 mm2. To compensate for the limited vertical field of view, 8 acquisitions were performed, moving the sample by 3.712 mm (50% of the vertical field of view) between each acquisition. Each acquisition consisted of 6000 projections recorded over a 360° rotation, each saved projection having an exposure time of 120 msec., resulting from the accumulation of 3 images of 40 msec.