Following such a major loss of diversity, Silurian communities were initially less complex and broader niched. Highly endemic faunas, which characterized the Late Ordovician, were replaced by faunas that were amongst the most cosmopolitan in the Phanerozoic, biogeographic patterns that persisted throughout most of the Silurian. The Late Ordovician mass extinction had few of the long-term ecological impacts associated with the Permian–Triassic and Cretaceous–Paleogene extinction events. Nevertheless, a large number of taxa disappeared from the Earth over a short time interval, eliminating and altering the relative diversity and abundance of certain groups. Cambrian-type fauna such as trilobites and inarticulate brachiopods never recovered their pre-extinction diversity.