Table 1.
Distribution of blades and bladelets according to blank type, presence of retouch, and the identified reduction phase.
The category initialization contains all blanks deemed to have had a role in the core’s shaping-out (e.g., fully cortical and crested blanks), while the category maintenance lumps all blanks related to the re-organization of the core convexities and maintenance of optimal flaking angles (e.g., lateral blades, neo-crested blanks, and technical blanks). The category semi-cortical includes blanks with different frequencies of cortex covering the dorsal face, while the category optimal contains all blanks with 0% cortex believed to have been obtained during the optimal reduction stage. Rounded percentages are given in brackets.
Table 2.
Descriptive statistics of the metric attributes of all classes of artifacts analyzed in this study.
Linear measurements are in millimeters while volume is in cubic millimeters. Elongation refers to the length to width ratio, while robustness refers to width to thickness ratio. Abbreviations: SE, standard error; SD, standard deviation; prcntl, percentile.
Fig 1.
Landmark digitization process on a bladelet with direct bilateral retouch.
A. Artifact oriented with the butt at the bottom; B. The 20x10 grid chosen in the software AGMT3-D to digitize surface semi-landmarks on the artifact’s 3D mesh; C. 3D rendering of the bladelet based on the set of landmarks digitized.
Table 3.
Variability report of the first 15 principal components.
Proportion of variance and cumulative proportion are percentages. PC stands for principal component.
Table 4.
Shape variability report across classes and the respective proportion (in %) caused by the three physical dimensions.
X represents the width, Y the length, and Z the thickness.
Fig 2.
Bivariate plot of the first and third principal components (PC1 versus PC3).
The illustrations in the x and y axes of the plot describe the variation of hypothetical shapes of blanks situated at the extremes of each principal component. Illustrations were created with the Warp tool in AGMT3-D). The mean of each group in the plot are identified with bigger dots. 95% confidence ellipses are plotted. For colors see the legend.
Fig 3.
Dendrogram representing the distance between the centroids of all groups analyzed in the first dataset.
The mean shapes for each group are also reported. The color coding of the mean shapes represents the spatial distribution of variability within each group.
Fig 4.
Selection of retouched bladelets.
a, c, n, p–q: alternate retouch; b, d, e–f, j: direct bilateral retouch; g, l–m: direct unilateral retouch; h–i, k, o: inverse retouch. Artifacts are oriented with the butt at the bottom of the figure. (Photos: A. Falcucci).
Table 5.
Variability report of the first 13 principal components.
Proportion of variance and cumulative proportion are percentages. PC stands for principal component.
Fig 5.
Boxplots with jittered points of volume values (in cubic millimeters) of retouched bladelets sorted according to retouch position.
For colors see the legend.
Fig 6.
Dendrogram representing the distance between the centroids of retouched bladelets sorted according to retouch position.
The mean shapes for each group are also reported. The color coding of the mean shapes represents the spatial distribution of variability within each group.
Table 6.
Shape variability report across retouched bladelets sorted according to retouch position and the respective proportion (in %) caused by the three physical dimensions, as well as the deviation from bilateral symmetry computed by AGMT3-D.
X represents the width, Y the length, and Z the thickness. Bilat. stands for bilateral.
Fig 7.
Boxplots with jittered points of PC2 (left) and PC3 (right) scores of retouched bladelets sorted according to retouch position.
Fig 8.
Bivariate plot of the second and third principal components (PC2 versus PC3) of retouched bladelets sorted according to retouch position.
The illustrations in the x and y axes of the plot describe the variation of hypothetical shapes of blanks situated at the extremes of each principal component. Illustrations were created with the Warp tool in AGMT3-D. The mean of each group in the plot are identified with bigger dots. For colors see the legend.
Fig 9.
2D shape analysis of the upper cross-section.
A and B are the bivariate plots of the first three principal components (PC1 versus PC2 and PC1 versus PC3) colored according to retouch position and with the mean of each group identified with bigger dots (see legend for colors). C displays the proportion of variance explained by the first eight principal components. D presents the shape variation of the first three principal components. SD stands for standard deviation.
Table 7.
Descriptive statistics of the mean angles (in degrees) of retouched bladelets sorted according to retouch position and localization.
Abbreviations: SE, standard error; SD, standard deviation; prcntl, percentile; dors., dorsal; ventr., ventral; bilat., bilateral; unilat., unilateral.
Fig 10.
Boxplots with jittered points of mean retouch angles (in degrees) of retouched bladelets grouped according to retouch position (i.e., alternate, direct bilateral, direct unilateral, and inverse) and localization (i.e., dorsal or ventral).
In the case of bladelets with direct bilateral retouch, dorsal left and dorsal right retouch computations were combined after finding no significant differences between the two edges.
Fig 11.
Bivariate plot of the second and third principal components (PC2 versus PC3) of retouched bladelets sorted according to typological definitions by Demars and Laurent [63] and Hahn [66].
The category retouched bladelet contains tools that are usually groups in the category of modified bladelet without further classification. In our case, this groups contains most of the artifacts with direct unilateral retouch. The illustrations in the x and y axes of the plot describe the variation of hypothetical shapes of blanks situated at the extremes of each principal component. Illustrations were created with the Warp tool in AGMT3-D. The mean of each group in the plot are identified with bigger dots. For colors see the legend.