Variabilidade craniométrica em uma população de oxymycterus amazonicus hershkovitz 1994 (rodentia: cricetidae)

Abstract

Oxymycterus is a genus of South American rodents (Cricetidae: Sigmodontinae) with a wide distribution in Brazil. Oxymycterus amazonicus (Hershkovitz 1994), the Amazonian representative of the genus, has as its northern limit the southern margin of the Amazon River, occurring approximately up to the middle course of the Tocantins, Xingu, Tapajós and Madeira rivers. This study is a contribution to the knowledge of the morphology of the genus, by analyzing the non-geographic variation of the mentioned species. A series of 79 specimens (57 males and 22 females), collected in the locality of Altamira (PA) and deposited in the scientific collection of the Zoology Department of the Emílio Goeldi Museum, was used for a pioneer study of the analysis of intrapopulational craniometric variation. Twenty-one cranial characters and five age classes were selected for the study. To identify morphological variation associated with ontogenic growth and sex, an analysis of variance (ANOVA) and a t-test were conducted. The results so far are only preliminary (considering that age-differentiated variation has not yet been analyzed) and indicate the absence of sexual dimorphism in the species.