Facial patterns in Cercopithecoidea and Hominoidea: a geometric approach

Area of Science:

• Primate evolutionary biology
• Comparative anatomy
• Geometric morphometrics

Background:

• Maxillofacial and orbital skull regions exhibit significant ontogenetic and phylogenetic variability.
• Understanding these variations is crucial for identifying evolutionary adaptations and classifying taxa.
• Geometric Morphometrics (GM) offers a powerful synthesis of traditional and modern morphometric techniques.

Purpose of the Study:

• To apply Geometric Morphometrics to analyze facial and orbital morphology in primates.
• To assess the validity of morphological differences for separating primate taxa (superfamilies, genera).
• To investigate how increased landmark data impacts taxonomic separation.

Main Methods:

• Standardized frontal photographs of primate crania were used.
• Two-dimensional coordinates of landmarks (LM) were recorded for the facial cranium.
• Factor analysis and distance computation were employed to compare datasets of the maxillofacial complex and orbital features.

Main Results:

• Morphological differences in the maxillofacial complex and orbital regions are sufficient for separating primate superfamilies and genera.
• The applied GM approach proved effective even within a heterogeneous sample.
• Increasing the number of landmarks enhanced the resolution and separation within the sample.

Conclusions:

• Geometric Morphometrics is a robust method for analyzing primate craniofacial diversity.
• Distinct morphological characters in the maxillofacial and orbital regions are evolutionarily significant for primate taxonomy.
• Detailed landmark analysis improves the ability to discern evolutionary relationships and taxonomic boundaries.