Morphological versus chromosomical and molecular divergence in two species of Eligmodontia

SIKES, ROBERT S.; MONJEAU, JORGE ADRIAN; BIRNEY, ELMER; PHILLIPS, CARLETON J.; HILLYARD, JEANNA

ZEITSCHRIFT FUR SAUGETIERKUNDE-INTERNATIONAL JOURNAL OF MAMMALIAN BIOLOGY

ELSEVIER

Año: 1997 vol. 62 p. 265 - 280

0044-3468

Karyotipic and mtDNA variation support the presence of at leat two distinct species of Eligmodontia in the Patagonian region of Argentina. No diagnostic morphological characters are available to identify these species reliably, and few data are available to assess reliably the degree of morphological differentiation between them. We used univariate and multivariate analyses of external morphological and cranial characters in a sample of Eligmodontia collected at 15 localities across northern Patagonia to test the hypothesis that these presumed species Eligmodontia morgani and Eligmodontia typus also are morphologically distinct. No single diagnostic morphological character was identified based on specimens for which independent identifications were available through mtDNA sequence and species-specific diploid numbers. However, discriminant function analyses were able to assign specimens reliably to correct species as independently determined, Cluster analyses based on various combinations of morphological characters showed some congruence with the other data set, but specimens of known mtDNA haplotype did not cluster together exclusively. These patterns suggest that although the genetic and karyological differences are substantial and potentially represent a deep divergence, these changes are not mirrored by equivalent morphological divergence.