Correlations between skull and mandible dimensions

Thursday 16 April 2009

BASILAR LENGTH AND MAXIMAL MANDIBULAR LENGTH IN ALLOHIPPUS AND EXTANT EQUUS:

SKULL-MANDIBLE CORRELATIONS

1. Skull and Mandible lengths

For a sample of 375 various extant Equus skulls and mandibles, the correlation is good: R2=0.97.

Regressions are:

– Basilar length of the skull (1) = [1.1775 * Maximal length of the mandible (1)] - 16.957.
– Maximal length of the mandible (1) = [0.8257 * Basilar length of the skull (1)] + 25.448.

2. Muzzle lengths

For a sample of 161 various extant Equus skulls and mandibles, the correlation is smaller: R2 = 0.89.

Regressions are:

– Skull muzzle length (5) = [1.0318 * mandible muzzle length (12)] + 7.9216.
– Mandible muzzle length (12) = [0.8645 * skull muzzle length (5)] + 4.507.

3. Muzzle widths

For a sample of 336 extant Equus, the correlation R2 is only 0.80.

Regressions are:

– Skull muzzle width (17) = [0.796 * mandible muzzle width (7)] + 16.8043.
– Mandible muzzle width (7) = [1.0105 * skull muzzle width (17)] - 6.187.

(1), (5), (7), (17) refer to the illustrated system of measurements of skulls and mandibles.

– Longueur basilaire sur Longueur de la mandibule
– Longueur de la mandibule sur Longueur basilaire
– Longueur du museau crânien sur Longueur du museau de la mandibule
– Longueur du museau de la mandibule sur Longueur du museau crânien
– Largeur du museau crânien sur Largeur du museau de la mandibule
– Largeur du museau de la mandibule sur Largeur du museau crânien