Recent advances in systematics have resulted in the development of statisti
cal approaches to phylogeny estimation and hypothesis testing. We present t
his emerging statistical perspective, distinguish it from the nonstatistica
l approach as commonly practiced, and demonstrate its application to 2 syst
ematic proposals from the recent literature on rodents: Mares and Braun's (
1996) retention of Andalgalomys contra Steppan (1995) and the conclusion of
Engel et al. (1998) that Calomys is a multitribal composite taxon. Systema
tic arguments and recommendations by Mares and Braun are critiqued in detai
l. We argue that the statistical approach provides a more objective and pow
erful basis for evaluating alternative phylogenetic hypotheses and a more s
table foundation for nomenclatural decisions.