Skull morphometry and vault sutures of Myrmecophaga tridactyla and Tamandua tetradactyla

This study aimed to examine the relations between skull size and the level of cranial vault sutures closure. A total of 50 Myrmecophaga tridactyla and 178 of Tamandua tetradactyla skulls were analyzed in relation to 18 skull dimensions. The skulls were grouped into three level of suture closure: none suture closured (level 0), many sutures closured (level 1) and all the sutures closured (level 2). The results indicated that among the 18 variables measured, 17 showed significant differences (p ≤ 0.01) between immature and sub-adults skulls of T. tetradactyla ; as well as between immature and sub-adult, besides immature and adult skulls of M. tridactyla . Myrmecophaga tridactyla sub-adults and adults had no significant difference among any of the 18 dimensions. The foramen magnum height in both species showed no significant difference (p > 0.05) among any of sutures categories. In principle, suture closure level and cranial dimensions are important to estimate age group for both species of anteaters, and both T. tetradactyla and M. tridactyla immature individuals have the foramen magnum height similar to adult animals.