Postweaning Ontogeny of the Skull of Didelphis albiventris

ABDALA, F.; FLORES, D.A.; GIANNINI, N.P.

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Lugar: Lawrence; Año: 2001 vol. 82 p. 190 - 200

0022-2372

Postweaning development of the skull of Didelphis albiventris was studied in juveniles(3.5-8 months), subadults (7.5-9.5 months), and adults (>9.5 months). Analysis of allometryof 15 skull measurements was performed on a continuous growth series of 52-61specimens to evaluate quantitative ontogenetic changes. Complex modifications occurredin cranial bones or regions such as the palate, processes for origin and attachment of jawmuscles, mandibular joint, frontal region, braincase, occipital bones, and petrosal. All measurements except zygomatic breadth were either positively or negatively allometric. Neurocranial components grew with strongly negative (<I) coefficients of allometry. Adultproportions of the masticatory apparatus arose from the counteraction of developmentaltrends; for example, the space for large temporal muscles was provided by isometric growthof the zygomatic breadth versus slower growth of the braincase. We interpret most of thepostweaning developments as a function of the shift from milk suckling to active mastication.