Error in geometric morphometric data collection: Combining data from multiple sources.

Area of Science:

• Primatology
• Anthropology
• Biometrics

Background:

• Morphometric analysis is crucial for understanding evolutionary relationships and biological variation.
• Quantifying measurement error is essential for reliable scientific conclusions.

Purpose of the Study:

• To compare two- and three-dimensional morphometric data.
• To assess the influence of intra- and interobserver and intermethod error on statistical analyses.
• To determine the impact of these errors on taxonomic and intraspecific variation.

Main Methods:

• Collected linear and three-dimensional (3D) morphometric data from 14 anthropoid crania using calipers, MicroScribe, NextEngine, and microCT scans.
• Employed Analysis of Variance (ANOVA) for linear data and geometric morphometric methods for 3D data, including principal components analysis and Procrustes distance calculations.
• Utilized UPGMA clustering to evaluate the grouping of trials by individual, observer, and method.

Main Results:

• Linear data showed most variance at the genus level, with observer error exceeding method error.
• In 3D data, interobserver and intermethod errors were comparable to intraspecific distances, with interobserver error being higher.
• While taxa generally separated well in morphospace, intraspecific overlap was substantial, indicating potential obscuring of patterns by error.

Conclusions:

• Caution is advised when combining data from multiple methods or observers, especially for intraspecific or closely related species analyses.
• Interobserver and intermethod error can obscure genuine biological patterns.
• Pre-data collection reliability assessments are recommended to mitigate error impacts.