Sebecidae is an extinct family of prehistoric mesoeucrocodylian crocodylomorphs. Sebecids were diverse, abundant and broadly distributed in South America (mostly in Argentina, Brazil and Bolivia) during the Cenozoic, until the Middle Miocene; although it has been suggested that at least some forms could have survived until the Miocene-Pliocene boundary in Brazil. This group included many medium and large - sized genera, from Sebecus to a giant indeterminate unnamed species from the Miocene.