go to the Tree of Life home page
Temporary Page
This is an archived version of a Tree of Life page. For up-to-date information, please refer to the current version of this page.



Scott J. Steppan
Unstriped ground squirrel (Xerus rutilus), Tarangire NP
taxon links [down<--]Rodentia [up-->]Callosciurini [up-->]Marmotini [up-->]Protoxerini [up-->]Xerini [up-->]Sciurini [up-->]Pteromyini 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
Phylogeny based on Mercer and Roth (2003) and Steppan et al. (2003).
Containing group: Rodentia


Mercer, J. M., and V. L. Roth, 2003. The effects of Cenozoic global change on squirrel phylogeny. Science 299, 1568-1572.

Steppan, S. J., B. L. Storz, and R. S. Hoffmann. 2004. Nuclear DNA phylogeny of the squirrels (Mammalia: Rodentia) and the evolution of arboreality from c-myc and RAG1. Mol. Phylo. Evol. 30:703-719.

Title Illustrations
Scientific Name Xerus rutilus
Location Tarangire National Park, Tanzania
Specimen Condition Live Specimen
Identified By David Bygott
Life Cycle Stage Adult
View Lateral
Copyright © 2005
Scientific Name Marmota
Creator Bill Hickey
Acknowledgements Photo courtesy U.S. Fish and Wildlife Service
Specimen Condition Live Specimen
About This Page

Scott J. Steppan

Department of Biological Science, Florida State University, Tallahassee, FL 32306-1100

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

Citing this page:

Steppan, Scott J. 2001. Sciuromorpha. Squirrels. Version 01 January 2001 (temporary). http://tolweb.org/Sciuromorpha/16456/2001.01.01 in The Tree of Life Web Project, http://tolweb.org/

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



Explore Other Groups

random page