A Catastrophic Death Assemblage of a New Species of Cormorant and Other Seabirds from the Late Pliocene of Florida

Abstract

ABSTRACT A new late Pliocene (upper Pinecrest beds, 2.4–2.0 Ma) fossil locality in Florida has produced thousands of bones and 137 whole and partial skeletons of a new species of cormorant, Phalacrocorax filyawi, that is related phylogenetically to Recent taxa currently restricted to the eastern north Pacific. Evidence from the bones and the stratigraphy of the site indicate that the cormorants died in a single catastrophic event, perhaps a red tide. At least eight other taxa of seabirds and shorebirds also were recovered from the site and include two new species of gull, Larus perpetuus and L. lacus, described herein. The depositional environment reflected by this fauna is a coastal lagoon and beach or shoreline habitat that rarely is preserved in the fossil record of Florida. The fossil cormorant and other seabirds from the Pliocene support molluscan evidence that the Florida Gulf Coast was characterized then by cold-water up welling and a highly productive marine system. Marine cormorants in the eastern Pacific may have extended into the Gulf of Mexico in the early Pliocene during submergence of the Panamanian Isthmus, but became extinct in this region by the end of the Pliocene.