The study tracked the waxing and waning of the range and diversity of families of mammals that inhabited the continental United States during this extended period.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/diversity-helped-mammals-survive-over-deep-time
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/economic-times-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/biodiversity
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mammals
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/united-states-america-us
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate-change
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/south-america
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/reptiles
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate-adaptation