The rodent family Muridae is the single most diverse family of mammals with over 1300 recognized species. We used DNA sequences from the first exon (∼1200 bp) of the IRBP gene to infer phylogenetic relationships within and among the major lineages of muroid rodents. We included sequences from every recognized muroid subfamily except Platacanthomyinae and from all genera within the endemic Malagasy subfamily Nesomyinae, all recognized tribes of Sigmodontinae, and a broad sample of genera in Murinae. Phylogenetic analysis of the IRBP data suggest that muroid rodents can be sorted into five major lineages: (1) a basal clade containing the fossorial rodents in the subfamilies Spalacinae, Myospalacinae, and Rhizomyinae, (2) a clade of African and Malagasy genera comprising the subfamilies Petromyscinae, Mystromyinae, Cricetomyinae, Nesomyinae, and core dendromurines, (3) a clade of Old World taxa belonging to Murinae, Otomyinae, Gerbillinae, Acomyinae, and Lophiomyinae, (4) a clade uniting the subfamilies Sigmodontinae, Arvicolinae, and Cricetinae, and (5) a unique lineage containing the monotypic Calomyscinae. Although relationships among the latter four clades cannot be resolved, several well-supported supergeneric groupings within each are identified. A preliminary examination of molar tooth morphology on the resulting phylogeny suggests the triserial murid molar pattern as conceived by Simpson (1945) evolved at least three times during the course of muroid evolution.
Bibliographical noteFunding Information:
We are grateful to the curators and associates of numerous museums who provided generous loans of tissue samples or allowed us to take samples of traditional museum specimens. We are particularly grateful to Lawrence Heaney, Bruce Patterson, Bill Stanley, and Steve Goodman (FMNH); Robert Voss (AMNH); Terry Yates and Bill Gannon (Museum of Southwestern Biology); Jim Patton (MVZ); Michael Carleton, Jeremy Jacobs, and Linda Gordon (NMNH); Mark Engstrom (ROM); Phil Myers and Antonia Gorog (UMMZ); Robert Timm, (KU); Richard Monk (TTU); Cibele Bonvicino (INCA); and François Catzeflis (Université Montpellier). For assistance with molecular work, we thank Lee Weigt, Julie Feinstein, and Jeff Groth. DNA sequencing was performed primarily at the Monell Molecular Laboratory of the American Museum of Natural History and the Laboratory of Molecular Systematics at the National Museum of Natural History. S.A.J. gratefully acknowledges support from postdoctoral fellowships at each of these institutions and additional financial support provided by the Department of Ecology, Evolution, and Behavior at the University of Minnesota. M.W. was supported by a graduate fellowship from the Center of Biodiversity and Conservation at AMNH. Useful comments on various versions of this manuscript were provided by Keith Barker, Link Olson, and anonymous reviewers. Finally, we are both unfailingly grateful to Robert Voss for intellectual guidance and moral support throughout the course of this project.
- Murid rodents