Resumen

GARCIA, João P.; OLIVEIRA, João A.; CORREA, Margaret M. O.  y  PESSOA, Leila M.. Morphometrics and cytogenetics of Gracilinanus Agilis and Cryptonanus spp. (Didelphimorphia: Didelphidae) from central and northeastern Brazil. Mastozool. neotrop. [online]. 2010, vol.17, n.1, pp.53-60. ISSN 0327-9383.

Species of the didelphid genera Gracilinanus and Cryptonanus are morphologically and cytogenetically very similar. Several qualitative characters, some of which exhibit intraspecific polymorphisms, have been used to distinguish these genera, but more data are needed to characterize them better. Samples of G. agilis and Cryptonanus spp. from nine localities in central and northeastern Brazil were analyzed. Multivariate analyses of craniodental measurements and descriptive statistics of external body measurements indicate that G. agilis is conspicuously larger than Cryptonanus spp., and that general size is the main factor distinguishing these forms. Size differences can be combined with qualitative characters making the differentiation between G. agilis and Cryptonanus spp. easier. Cytogenetic analyses, including the first description of C-bands and Ag-NORs of G. agilis, revealed that the karyotypes of G. agilis and Cryptonanus sp. from Barão de Melgaço, Mato Grosso, are very similar, except for the fourth autosomal pair and the X chromosome.

Palabras clave : Differentiation; General size; Karyotypes; Mouse opossums.

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