This list of fossil arthropods described in 2009 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods that have been described during the year 2009, as well as other significant discoveries and events related to arthropod paleontology that occurred.

This paleomammalogy list records new fossil mammal taxa that were described during the year 2011, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.