Fig 6. Linear relationship between ontogeny (using skull length as a proxy) and the averaged degree of sutural closure in A. mississippiensis (n = 46).

This relationship has a Pearson’s coefficient of correlation (r) of -0.79. The approximate onsets of sexual maturity and skeletal maturity for females and males are mapped on the trend line. Below the trend line are the different ontogenetic categories, indicated with the same color code as that used in previous figures. Above the trend line are exposed the estimated diet of these animals at the time of death, based on previous studies [71,72]. Each data point (i.e., each skull) is characterized by its sex and domestic or wild status (see legend in black square). This relationship shows an obvious decrease in the degree of sutural closure as ontogeny proceeds, in other words, sutures become wider.