## 2 Materials and Methods
All individuals have been characterised chemically through wavelength dispersive X-ray fluorescence (WD-XRF) and mineralogically through powder X-ray diffraction (PXRD). For analysis by WD-XRF, samples of about 15 g were taken from each individual. The superficial layers were mechanically removed, and the samples were milled in a tungsten carbide cell mill, the Spex Mixermodel 8000. The chemical composition was determined from powder dried in an oven for 12 h at 105 C. Two 30 mm glass bead replicates were made by mixing 0.3 g of the dried sample with 5.7 g of lithium tetraborate (Li2B4O7) flux (1/20 dilution) and 5 mg of lithium iodide (LiI) as a release agent to determine the major and minor elements. This mixture was homogenised, placed in a 95% Pt, 5% Au crucible, and melted in a fully automatic bead preparation system, PANalytical PerlY-3, at 1125 C. Pressed powder pellets were made using 6 g of specimen mixed with 2 mL of a binding agent solution of n-butyl methacrylate synthetic resin (Elvacite(r) 2044) in acetone at 20% by mass to determine trace elements. This mixture was manually homogenised in an agate mortar to dryness and placed on a base of boric acid (H3 BO3) in an aluminium vessel of 40 mm diameter subjected to a pressure of 200 kN for a period of 60 s using a Herzog press. Due to the long duration of the research project, two different XRF instruments were used to determine the concentrations. First, in the case of individuals MOS001-MOS054, a Phillips PW2400 spectrometer with an Rh excitation source was used. Then, individuals MOS061-MOS083 were analysed using an Axios(tmAX)-Advanced PANalytical spectrometer with an Rh excitation source. Both spectrometers were calibrated by a suite of 56 international Geological Standards. Interferences were considered, and matrix effects were corrected. For individuals MOS061 to MOS083, these corrections were made using the PANanalytical Pro-Trace software for trace elements. The elements determined were: Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, V, Cr, MnO, Fe2O3 (as total Fe), Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Nb, Mo, Sn, Ba, Ce, W, Pb, and Th. For individuals MOS001 to MOS054, Na2O was determined from the pressed powder pellet, while for individuals MOS061 to MOS083, it was determined from the glass bead replicates. Finally, for individuals MOS061 to MOS083, the trace elements Sc, La, Sm, and Yb were also determined using only PANalytical synthetic standards, and their concentrations must be considered semiquantitative. Major and minor elements are expressed as concentrations of oxides in mass fraction percentage (\(w\)%). Trace elements are expressed as elements in \(w\) mg/kg. Loss on ignition (LOI) (expressed as \(w\)%) was determined by firing 0.3 g of the dried specimen at 950 C for 3 h. Calciations were carried out in a Heraeus muffle model M-110 using a heating rate of 3.4 C/min and free cooling. For the statistical data treatment, the concentrations of Mo and Sn were discarded due to analytical imprecision, as were those of Co and W because of possible contamination from the tungsten carbide cell of the mill used. P2O5 concentrations were not used in the data treatment as some values were considered erratic, and some individuals were pushed out of their group. Such values can be due to contamination during burial, for example, from organic matter [32] (and references therein). However, the general influence of this element was low, and the main structure defined in the data set was preserved after it was discarded. Sc, La, Sm, and Yb were discarded for the general data treatment and only used for comparison with other projects. The mineralogical characterisation of all individuals was performed using PXRD. The previously prepared powder specimens were manually side-loaded and pressed with frosted glass in a cylindrical sample holder of 27 mm diameter and 2.5 mm high (PW 1811/27).