DOI: 10.5061/dryad.2rbnzs7v7
title: Supporting information for: Clade-specific elemental signatures across an Early Triassic marine fauna pave the way for deciphering the affinities of unidentifiable fossils

description: 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 spectra. We then
 statistically demonstrate the existence of a geochemical discrimination
 between specimens of different clade despite intra-clade mineralogical
 variability, and build a “elemental-comparative taxonomic identification”
 model accordingly. The latter, that goes beyond the simple distinction of
 tissue nature or type of preservation, is all the more important as it
 appears to hold the potential to identify some hitherto unrecognizable
 specimens of the fossil record.
description: # Supporting information for: **Clade-specific elemental signatures across
 an Early Triassic marine fauna pave the way for deciphering the affinities
 of unidentifiable fossils** 
 
 The supporting information consists of: 
 
 **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.        - Data S2 - Mean µ-XRF
 spectrum of each studied zone in respect to Data S1. The data presents the
 mean value of photons measured per pixel ("counts" column) per
 energy level ("energy" column) over the sampled area. The
 documents are in .CSV format.        - Data S3 - Mean µ-XRF spectrum of
 each studied zone regrouped per- specimens (following the Table S1 naming
 convention) such as to be statistically analysed using R software. The
 documents are in .CSV format. 
 
 **S2 - PDF file**
 **("S2_File_Supplementary_Materials_Smith_et_al.pdf")** **including:**        - Figure S1        - Figure S2        - Supplementary text        - The µXRF spectra morphological descriptors approach        - Data acquisition setups        - Figure S3        - Table S1        - References 
 
 **S3 - R data analysis script**
 **("S3_File_R_script_Smith_et_al.R")**