Supplementary material from: ZooMS confirms geometric morphometrics species identification of ancient sheep and goat
Data files
Oct 18, 2023 version files 444.40 MB
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README.md
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SI-Fig1_Proba-ID.pdf
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SI-Fig2_Boxplot-Chrono-Sites.pdf
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SI-Fig3_PCA.pdf
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SI-table1_Referenciel-actuel.xlsx
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SI-table2_Referenciel-Zooms.xlsx
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SI-table3_Data_TPS_ZooMS.xlsx
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ZooMS_Spectra.zip
Abstract
Geometric morphometrics can effectively distinguish isolated third lower molars of present-day sheep and goat, but its applicability to archaeological specimens has yet to be established. Using a modern reference collection of 743 sheep and goats and a 2D-landmark-based geometric morphometric (GMM) protocol, this study aimed to morphometrically identify 109 archaeological specimens, used as case studies, dating from the Late Neolithic to the modern period/era. These morphometric identifications were then compared to molecular identifications via collagen peptide mass fingerprinting, known as Zooarcheology by Mass Spectrometry (ZooMS). ZooMS confirmed the morphometric identifications for 104 specimens, with the five misidentified specimens all morphometrically identified as goat.
Modern sheep and goats have larger teeth and distinct shapes compared to their archaeological counterparts, suggesting strong differences between archaeological and modern specimens potentially linked with recent breed improvement or geographic origin of the specimens. In addition, for both species, some of the archaeological dental morphologies do not match with any of our modern references.
This study validates the applicability of geometric morphometrics for identifying isolated archaeological sheep and goat teeth. It represents a stepping stone for future, non-destructive, bioarchaeological studies of the two species.
README: Supplementary data
SI Table 1 : List of modern specimens used as geometric morphometrics modern referentiel. Code GMM corresponds to the specimen names, Collection to the place where specimens were stocked, Correspondant to the person in charge of the collection, Origin to the place where specimens were collected, Genus and Species to the species, M3 wear to the estimated wear using Payne stages, related to the estimated age. A blank field indicates that the information is not known.
SI Table 2 : List of archaeological specimens sampled for ZooMS analyses. The column names are the same as in SI Table 1, with the addition of the city of the archaeological site (City), its name (Archaeological Site) and the number associated (Number Archaeological Site), US, which corresponds to the stratigraphic units, TPQ and TAQ, which are the terminus post quem and terminus ante quem, the chronology of each sample, and the morphometric (GMM identification) and ZooMS identification of each sample. A blank field indicates that the information is not known.
SI Table 3 : Geometric morphometric data set with scaled coordinates of modern and archaeological specimens.The first column corresponds to the name of each specimen (Code GMM), the second to the collection where the specimens are stocked, and the third to the identifications of each specimen (e.g. modern/archaeological and sheep/goat, Groups). All other columns contain the coordinates (XY) for each landmark and sliding semi-landmark (1 to 55).
SI Figure 1: Identification probability of each LDA for each archaeological sample, sorted by archaeological site numbers. The upper part of the graph, in green, corresponds to the probability of each LDA for specimens identified as sheep by geometric morphometrics, while the lower part, in blue, corresponds to goats identified by geometric morphometrics. The colour of each box plot corresponds to the ZooMS identification. Specimens with a red star are misidentified by geometric morphometrics. Specimens with a black star are those identified as both goat and sheep by LDA. The most numerous identification was retained.
SI Figure 2: Boxplot showing differences in log centroid size for goats and sheep between archaeological sites and chrono-cultural occupation. See Table 2 for numbers of archaeological sites. N refers to Neolithic; Br to Bronze Age; Ir to Iron Age; Ant to Antiquity; MA to Middle Ages; MOD to Modern Period; ACT to Advanced Contemporary and Out Str to Out of Stratigraphy.
SI Figure 3: Two first axes of the PCA showing variation between modern (dark) and archaeological (light) independently for sheep and goat.
SI File 1: ZooMS MALDI-TOF-MS spectra for each archaeological sample. The first column corresponds to mass to charge (m/z) ratio and the second to absorbance intensity. Each sample was analysed in triplicate, resulting in three files per sample corresponding to spectrum a, b and c, which where then averaged. See SI Table 2 for sample names