[Toward exploration of morphological disparity of measurable traits of mammalian skull. 1. Interrelation between different forms of group variation].

This research explores the relationship between group variations, such as age, sex, and geography, of measurable skull traits in six mammal species. It suggests that there is a wide diversity of interrelations between these variations and that understanding these relationships goes beyond simple statistical analysis.

Understanding the Research

This research explored the interrelation between different forms of group variation (FGVs), using measurable skull traits from six mammal species:

• Pine Marten
• Polar Fox
• Przewalskii Horse
• 3 Jird species

FGVs considered in this study included age, sex, geographic differences, inter-species differences, and differences among breeds. These FGVs were analyzed through dispersion analysis, specifically model III, MANOVA, with skull traits considered as the dependent variables.

Results and findings

The data from this research showed a wide variety of interrelations between FGVs. The analysis revealed that the statistical analysis of the significance of joint effects of FGVs does not replace the analysis of numerical interrelations of their dispersion portions.

Conclusion of the study

The researchers concluded that merely looking at such interrelations as simple “statistical regularities” like the Kluge-Kerfoot phenomenon is unproductive. As a result, the sets of characters are not to be considered as statistical groups.

On a different note, the research postulates a “background” age variation, with other FGVs being its derivatives. With the assumption that other factors, structuring the morphological disparity under investigation, are absent, a positive correlation between FGVs is expected. If significant deviations from the projected correlation are observed, other factors, which cannot be reduced to the age variation, need to be considered.

Consideration of Individual Cases

In the study of specific cases, the research considers possible interpretations of interrelations between the age variation and other FGVs in carnivores. The research also considers the impact of domestication on the craniological variation in the Przewalskii horse, concluding that negative correlation between geographic and inter-species differences in the jirds could potentially be interpreted as evidence for the speciation described by the punctuated equilibrium model.