| Summary: | The Pisco Formation (middle Miocene-late Pliocene, southern Peru) is known for its exceptional fossil record of marine vertebrates. This is perhaps the most significant record of the world for the Neogene, due to the extraordinary preservation, the elevated concentration of fossils, and their great diversity, including sharks and bony fish, marine turtles and crocodiles, seabirds, baleen and toothed whales, seals, and marine sloths. Since the '80s of the past century, several studies demonstrated that these fossils are concentrated in some restricted areas, which represent the main vertebrate-bearing fossil localities of the Pisco Formation. However, data about the diversity of the entire fossil assemblages were only published for some taxonomic groups or as preliminary faunal lists. Moreover, these studies generally lack a detailed geological and stratigraphical background, thus leaving unresolved the vertical and horizontal distribution of the fossils in the exposed strata of a given locality. This work presents for the first time a detailed map reporting all fossil vertebrates cropping out at Cerro Colorado, the locality where the holotypes of the giant raptorial feeding sperm whale Livyatan melvillei, the long-snouted beaked whale Messapicetus gregarius and the sea turtle Pacifichelys urbinai were found. Several hundreds of fossil marine vertebrates are identified and reported in a geological map and in a joined stratigraphic section. All the fossils are from the lower strata of the Pisco Formation, dated in this area to the late middle or early late Miocene; they are particularly concentrated (88%) in the stratigraphic interval from 40 to 75 m above the unconformity with the underlying Chilcatay Formation. The impressive fossil assemblage includes bone remains belonging predominantly to cetaceans (81%), represented by mysticetes (cetotheriids and balaenopteroids) and odontocetes (kentriodontid-like delphinidans, pontoporiids, ziphiids, and physeteroids including L. melvillei). Seals, crocodiles, sea ...
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