Data and code for: Sexual dimorphism and predominance of fluctuating asymmetry over directional asymmetry in human cranial shape: a multi-view geometric morphometric analysis

This repository contains the raw landmark data, MorphoJ exports, processed results, and R analysis scripts supporting a geometric morphometric study of sexual dimorphism and bilateral asymmetry in human cranial shape. Study overview The dataset comprises 123 dry adult human crania (without associated mandibles) drawn from the historical teaching osteological collections of six Chilean universities: Pontificia Universidad Catolica de Valparaiso, Universidad de Playa Ancha, Universidad Andres Bello (Vina del Mar campus), Pontificia Universidad Catolica de Chile, Universidad Austral de Chile and Universidad de La Frontera. Specimens were not acquired for the purposes of this study; no individual-level identifying information (documented sex, age at death, or ancestry) was available or used. Sex was morphologically estimated following Buikstra and Ubelaker (1994). Each specimen was photographed in up to five standardized anatomical projections (anterior, posterior, superior, inferior, lateral); effective sample size varies slightly by view (n = 100-123) due to structural damage, fragmentation, or landmarks that could not be unambiguously identified in a given projection (see Table S1 in the associated supplementary material for full per-view completeness). Directional asymmetry (DA) and fluctuating asymmetry (FA) were quantified via Procrustes ANOVA on object-symmetric configurations for four bilateral views (anterior, posterior, superior, inferior); the lateral view was excluded from symmetry analysis, as a single-side profile lacks reflectable landmark pairs. Repository contents Raw landmark data: TPS files (TPS_anterior.tps, TPS_posterior.tps, TPS_superior.tps, TPS_inferior.tps, TPS_lateral.tps) digitized in tpsDig2 v2.32. MorphoJ exports: SKULLS.morphoj workspace file and five PC_scores_CovMatrix_view_ProcCoord_pooled_by_SEX.txt files (Procrustes-superimposed coordinates and principal component scores per view). R analysis scripts (geomorph v4.1.1, R-universe build; RRPP v2.1.2). Script 01_symmetry_pipeline_FINAL_EN.R performs the bilateral symmetry analysis using bilat.symmetry(), the Procrustes ANOVA of directional and fluctuating asymmetry, and the corrected per-specimen FA magnitude (9999 permutations, seed = 2026). Script 02_allometry_corrected_EN.R performs the allometric regression using log(centroid size) as the size predictor, plus confirmatory tests of the sex effect on cranial shape. Script 03_symmetry_sexFA_VERIFIED_EN.R performs the permutational ANOVA testing the effect of sex on the multivariate asymmetric shape component. Processed results: per-specimen PCA, LDA, and k-means classification results by view, allometry and sex-shape test outputs, confusion matrices, a cross-view summary table, and the definitive bilateral symmetry object (9999 permutations). Ethical statement Human skeletal remains in this study were pre-existing teaching specimens held by the respective institutions prior to data collection. In accordance with recommendations for the ethical use of human cadaveric material in anatomical research, every effort was made to follow applicable local and international ethical guidelines and laws governing the acquisition, storage, photographic documentation, and analysis of human skeletal remains. Reproducibility notes All permutation-based analyses use a fixed random seed (2026) and 9999 iterations. geomorph v4.1.1 must be installed from R-universe, not CRAN. Scripts are numbered in their intended execution order; script 03 requires the .rds output of script 01 as input. Column and file names use American English throughout. Excluded from this repository Finalized figures (PDF/TIFF) and manuscript-formatted supplementary tables (.docx) are not included here, as they are editorial products rather than raw or intermediate data.