Unexpected finds in the National Capital Area provide clues to species distribution during different points in geologic history. A fossilized dugong rib bone found during construction of the Suitland Parkway indicates that these marine mammals, only found in Indo-Pacific oceans today, were present in an ancient ocean once covering this region 54-5 million years ago (MYA). Ancient oceans were a dangerous place for these Metaxytherium dugongs, which were likely hunted by predators such as megalodon sharks (16-2.6 MYA), whose large fossilized teeth are present in abundance in this region and in the Rock Creek Park collections.
The presence or absence of specific organisms at specific points in geologic time and evidence of interactions between them can shed light on the ecology of ancient ecosystems. The dugong fossil featured here shows marks which indicate an ancient predator-prey relationship between these organisms and the large predatory megalodon.
