Supporting information for: Clade-specific elemental signatures across an Early Triassic marine fauna pave the way for deciphering the affinities of unidentifiable fossils

In palaeontology, the observation of morphological characters is at the heart of species determination. Nonetheless, since most fossils have undergone considerable morphological loss, distortion, and/or flattening throughout their taphonomic history, the use of visual techniques often remains limited. Complementary approaches such as geochemical analyses or molecular palaeontology are increasingly developed. However, them as well remain limited by the preservation state and diagenetic overprinting of the vast majority of fossils. Based on data obtained by state-of-the-art non-destructive synchrotron micro-X-ray fluorescence (µXRF) major-to-trace elemental mapping of Early Triassic Paris Biota fossils, we show here, at least within a single fossil fauna, the existence of a clade-specific elemental signature. Using complete multi-elemental µXRF spectra instead of elemental quantifications/concentrations, we set a data-formatting protocol that allows us to compare the morphology of the spe..., , , # Supporting information for: **Clade-specific elemental signatures across an Early Triassic marine fauna pave the way for deciphering the affinities of unidentifiable fossils**

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The supporting information consists of:

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**S1 - Raw data** **(\"S1_File_raw_data_Smith_et_al.zip\")** **including:**

              - Data S1 - Pictures of the analysed samples exported from PyMCA, with the studied zones highlighted by shaded areas. Files are sorted per experimental session (DiffAbs-2018, PUMA-2021, and PUMA-2024).

* Image zones_PUMA_2021: 96 documents (pictures in PDF format)

- Image zones_diffabs_2018: 84 documents (pictures in PDF format)

* Image zones_PUMA_2024: 84 documents (pictures in PDF format)

For each picture, the axes correspond to the pixel rows and columns, as set by default in PyMCA. File names follow the conventions in Table S1 and are completed with “sed” or “foss” to indicate whether the studied area corresponds to sediment or fossil material, respectively.

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