Savanna-like ecosystems were present at high latitudes in North America during much of the Neogene. Present-day African savannas, like the Serengeti, have been proposed to be modern analogs of these paleosavannas, particularly those from the middle Miocene of the Great Plains region of the United States. Both these extant and extinct savannas contain a preponderance of artiodactyl (even-toed ungulate) species; however, the taxonomic composition of each fauna is different. While present-day African savannas are dominated by ruminants (primarily bovids), the Neogene savannas of North America were dominated by a diversity of both camelid and non-bovid ruminant families. This study provides a quantitative test of the similarity of the artiodactyl faunas of the North American Neogene paleosavannas to those of the modern-day African savannas. A correspondence analysis of ecomorphological features revealed considerable overlap between modern and fossil faunas. The morphospace occupation of the extinct North American ruminants falls within that of the African bovids. Some of the extinct camelids also fall within this same morphospace, but many do not, perhaps indicating an environmental difference such as greater aridity in Neogene North America. The diversity and disparity of artiodactyl faunas through the Neogene of North America changed along with changing temperatures and precipitation regimes. The taxonomic and ecomorphological diversity of the Serengeti ruminant fauna is statistically comparable to those North American paleofaunas occurring during or immediately after the Middle Miocene Climatic Optimum (MMCO), but the later, more depauperate faunas are no longer comparable. This study quantitatively analyzes artiodactyl communities as they changed with the cooling and drying trend seen during the Neogene.

在新近纪的大部分时间里，北美高纬度地区都存在像热带稀树草原一样的生态系统。如今，像塞伦盖蒂（Serengeti）这样的非洲稀树草原被认为是这些古稀树草原的现代类似物，特别是来自美国大平原地区中新世中期的那些。这些现存的和已灭绝的稀树草原都含有大量的偶极动物基（偶蹄类）。但是，每个动物区系的分类组成是不同的。虽然当今的非洲热带稀树草原以反刍动物（主要是牛科动物）为主，但北美的新近纪热带稀树草原却以骆驼科和非生物反刍动物家族为主。这项研究提供了定量测试的北美新近纪古热带稀树与现代非洲稀树大草原的偶蹄动物区系的相似性。对生态形态特征的对应分析表明，现代动物和化石动物之间存在相当大的重叠。灭绝的北美反刍动物的形态空间占领属于非洲牛科动物。一些已灭绝的骆驼科动物也属于同一形态空间，但许多没有，这可能表明存在环境差异，例如北美新近发展的干旱程度更高。随着温度和降水制度的变化，北美新近纪中的偶生动物区系的多样性和差异也随之变化。塞伦盖蒂反刍动物区系的分类学和生态形态多样性在统计学上可与中新世中期最佳气候（MMCO）期间或之后发生的北美古植物区系相媲美，但后来更多，贫化的动物群不再具有可比性。