Cranial ontogeny on Lutreolina crassicaudata (Didelphimorphia: Didelphidae): a comparision with Didelphis albiventris.

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

ACTA THERIOLOGICA

Año: 2003 vol. 48 p. 1 - 9

0001-7051

Abstract Metatherian experience the greatest developmental changes during extrauterine life. Following previous studies on Didelphis albiventris Luna, 1840, we examined the posweaning cranial allometry of size of neotropical marsupial Lutreolina crassicaudata (Desmarest, 1804). Our aim was to compare growth patterns of both species to identify traits particular to each species and traits common to both species. This may contribuye toward identifying a common developmental plan for didelphids. We measured 15 cranial variables in 32-43 specimens from just-weaned young to old adult. Total lenght of the skull was the estimator of overall size in least squares and reduced major axis regressions. The skull of Lutreolina grows at a rate slower than overall change in size in its neurocranial components, palate, and postcanine rows, and its grows relatively faster in the rest of the splachnocranium. This pattern closely resembles that of Didelphis albiventris, from which it differs mainly in the allometry of the puzzle. In both species, allometry axplains most postweaning changes of the trophic apparatus on functional grounds, in relation to interspecific differences in diet. We hypothesize that most local allometric departures from a generalizad didelphid plan would relate to main dietary trends.