Temporary Page


Rice rats, spiny mice, marsh rats

Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
taxon links extinct icon Not Monophyletic[down<--]Sigmodontinae Interpreting the tree
close box

This tree diagram shows the relationships between several groups of organisms.

The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.

example of a tree diagram

You can click on the root to travel down the Tree of Life all the way to the root of all Life, and you can click on the names of descendent subgroups to travel up the Tree of Life all the way to individual species.

For more information on ToL tree formatting, please see Interpreting the Tree or Classification. To learn more about phylogenetic trees, please visit our Phylogenetic Biology pages.

close box

Tree based on Weksler (2003), Steppan et al. (unpubl. data), Dickerman (1992), Steppan (1995, 1996), Voss and Carleton (1993), Dickerman and Yates (1995), and Myers et al. (1995).

Containing group: Sigmodontinae

Discussion of Phylogenetic Relationships

Resolution of oryzomyine relationships is severely handicapped by the paraphyletic or polyphyletic nature of Oryzomys, the lack of taxonomic overlap among studies, and disagreements among studies.

Other Names for Oryzomyini


Dickerman, A. W. 1992. Molecular systematics of some New World muroid rodents. Ph.D. dissertation, University of Wisconsin-Madison.

Gardner, A. L., and J. L. Patton. 1976. Karyotypic variation in oryzomyine rodents (Cricetinae) with comments on chromosomal evolution in the neotropical cricetine complex. Occ. Pap. Mus. Zool., La. State Univ. 49:1-48.

Steppan, S. J. 1995. Revision of the leaf-eared mice Phyllotini (Rodentia: Sigmodontinae) with a phylogenetic hypothesis for the Sigmodontinae. Fieldiana: Zool. 80:1-112.

Steppan, S. J. 1996. A new species of Holochilus (Rodentia: Sigmodontinae) from the middle Pleistocene of Bolivia and its phylogenetic significance. J. Vert. Paleont. 16:522-530.

Voss, R. S., and M. D. Carleton. 1993. A new genus for Hesperomys molitor Winge and Holochilus magnus Hershkovitz, with comments on phylogenetic relationships and oryzomyine monophyly. Am. Mus. Novitates 3085:1-39.

Title Illustrations
Click on an image to view larger version & data in a new window
Click on an image to view larger version & data in a new window
Scientific Name Oryzomys palustris
Creator R.K. LaVal
Specimen Condition Live Specimen
Identified By R.K. LaVal
Life Cycle Stage Adult
About This Page

Correspondence regarding this page should be directed to Scott J. Steppan at

All Rights Reserved.

Citing this page:

Tree of Life Web Project. 1996. Oryzomyini. Rice rats, spiny mice, marsh rats. Version 01 January 1996 (temporary). http://tolweb.org/Oryzomyini/16587/1996.01.01 in The Tree of Life Web Project, http://tolweb.org/

edit this page
close box

This page is a Tree of Life Branch Page.

Each ToL branch page provides a synopsis of the characteristics of a group of organisms representing a branch of the Tree of Life. The major distinction between a branch and a leaf of the Tree of Life is that each branch can be further subdivided into descendent branches, that is, subgroups representing distinct genetic lineages.

For a more detailed explanation of the different ToL page types, have a look at the Structure of the Tree of Life page.

close box


Page Content

articles & notes



Explore Other Groups

random page

  go to the Tree of Life home page