The interaction between nonmetric and metric cranial variation

Area of Science:

• Anthropology
• Human Anatomy
• Bioarchaeology

Background:

• Previous research suggested no relationship between cranial discrete (nonmetric) and metric traits.
• The consensus was that these two types of skeletal measurements were independent.

Purpose of the Study:

• To investigate interrelationships between cranial discrete traits and skull measurements.
• To test the hypothesis of independence between nonmetric and metric cranial characters.

Main Methods:

• Analysis of 50 discrete cranial traits and 23 metrical characters in American Negro males.
• Application of univariate t-tests and multivariate T2 tests.
• Utilizing multivariate analysis to synthesize regional skull variation patterns.

Main Results:

• Statistically significant associations were found more frequently than expected by chance between discrete and metrical cranial characters.
• Multivariate analysis revealed numerous interrelations between skull size/shape and discrete traits.
• A low but observable influence of metrical variation on nonmetric morphology (and vice versa) was detected.

Conclusions:

• Cranial discrete traits and metric measurements are not unrelated, contrary to prior consensus.
• Skull size and shape are associated with nonmetric cranial morphology.
• These findings highlight the interconnectedness of skeletal variation in human crania.