CRANIAL ONTOGENY OF CALUROMYS PHILANDER (DIDELPHIDAE, CALUROMYINAE): A QUALITATIVE AND QUANTITATIVE APPROACH

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

JOURNAL OF MAMMALOGY

ALLIANCE COMMUNICATIONS GROUP DIVISION ALLEN PRESS

Año: 2010 p. 539 - 550

0022-2372

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:9.0pt; font-family:Arial; mso-fareast-font-family:"Times New Roman"; mso-font-width:99%; mso-ansi-language:ES; mso-fareast-language:ES;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> The ontogeny of the skull, seen from a quantitative allometric perspective, has been the subject of research in didelphid, microbiotheriid, and dasyurid marsupials. Following previous work, we describe and compare postweaning stages of cranial development in the woolly opossum Caluromys philander, member of a distinct lineage of didelphids. We identified 31 qualitative morphological changes between juveniles and adults, many of which related to the trophic apparatus. Early development of the paracanine fossa in the snout, correlated with the presence of well-developed canines in juveniles, is a remarkable difference in the ontogeny of C. philander as compared to other marsupials studied so far. We performed bivariate and multivariate analyses of allometry on a database composed by 14 cranial measurements and 45 specimens. Allometric scaling showed that braincase is relatively small in adulthood, whereas other neurocranial components, particularly the orbit, grew isometrically along its length.  The palate becomes elongated by the combination of the isometry of its length and the “negative” allometry of its width. The rostrum lengthened whereas its height remained proportionally constant. In relative terms, the temporal fossa expanded inward following the marsupial model that combines the negative allometry of the braincase and the isometry of the zygomatic breadth. The mandible increased robustness. The skull ontogeny of C. philander has shares four allometric trends with two didelphids (Didelphis albiventris and Lutreolina crassicaudata) and two australidelphians (Dromiciops gliroides and Dasyurus albopunctatus) previously studied. Three of these trends, breadth of palate, breadth of braincase and height of occipital plate were allometrically negative, whereas height of the dentary was positive. These common allometric trends may be interpreted as symplesiomorphic for marsupials, suggesting a high degree of conservatism in the skull development of Caluromys and other marsupials.