Dataset and R code for "The olfactory nerve foramen as an accessible osteological character: variation among seabird orders"

This archive contains the data and the annotated R code required to reproduce all analyses in the associated manuscript, "The olfactory nerve foramen as an accessible osteological character: variation among seabird orders" (S. K. B. de Melo & C. J. Carlos). The study examines variation in the olfactory nerve foramen (ONF) of the avian skull across four seabird orders, based on cranial measurements of 635 adult specimens from 23 species. Contents: • seabird_cranial_onf_measurements.xlsx — specimen-level cranial measurements (mm). • onf_seabirds_analysis.R — annotated R script reproducing all analyses (descriptive statistics, a PCA-based cephalic size index, allometry, phylogenetic signal, rank-based ANCOVA, phylogenetic ANOVA, and PGLS). • birdtree_100_trees.nex — 100 phylogenetic trees from the BirdTree project (Jetz et al. 2012), Hackett backbone. • README.txt — full description of files, variables, and reproduction steps. See README.txt for details. Code is released under the MIT License; data under CC BY 4.0. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Finance Code 001.