Species-Specific Structure of the Frontal Part of the Skull in the Sable ( Martes zibellina ) and the European Pine Marten ( Martes martes )

Comparative analysis of three craniometric traits that characterize the length-to-width ratios in the frontal surface of the skull in the sable and the pine marten was performed. The character Δ (delta) was proposed for the first time as the distance from the postorbital narrowing to the line drawn between the postorbital processes in the sagittal plane. When analyzing tutorial ( n = 431) and test samplings ( n = 154), the high discriminating capacity of this trait was revealed for species identification based on craniological material. A joint analysis of variations in this “Δ” trait with the breadth of the postorbital constriction revealed for the first time their species-specific interrelations, i.e., the presence of opposite trends in the ontogeny of both model species. Discriminant analysis showed a high level (more than 97%) of correct species identifications based on the newly proposed trait.