Non-allometric variation in the brown-throated sloth bradypus variegatus (Schinz, 1825) skull (mammalia, pilosa, bradypodidae)

Abstract

Brown-throated sloth Bradypus variegatus (Schinz, 1825) is a monomorphic mammal, and its skull ontogeny is poorly known. Here, we present a study of the ontogenetic allometric relationship between skull size and shape in 21 specimens of different sizes, for which size and shape were determined by means of geometric morphometric methods. Results indicate that skull shape variation can hardly be explained by skull size. Several studies have shown unique morphological traits of sloths from mammalian norms, affecting varied phenotypic traits from skeletal parts to soft tissues. This non-allometric scaling of skull form in sloth can be seen as another uniqueness of this taxonomic group.