2011/09/01 by Mark D. Uhen, Nicholas D. Pyenson, Thomas J. DeVries +2 · 2 citations
Environmental Science · Agricultural and Biological Sciences · Earth and Planetary Sciences · #Marine animal studies overview #Cephalopods and Marine Biology #Marine and coastal plant biology #Paleontology #Geology #Structural basin #Southern Hemisphere #Section (typography) #Geography
paper · doi:10.1666/10-162.1
openalex publication_date 2011/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Three new specimens of middle Eocene cetaceans are reported from the Pisco Basin of southern Peru. All three specimens originate from the Paracas Formation and their minimum age is constrained to about 37 Ma using 40Ar/39Ar dating of ash collected ∼100 m up section from the source localities. Two new genera of archaeocete cetaceans are described along with additional material of another distinctive protocetid, which is not named pending the discovery of more complete material. Phylogenetic analysis resolves the two new genera within Basilosauridae, while the unnamed protocetid is closely related to Eocetus. The discovery of crownward protocetids in South America demonstrates that early cetaceans may have dispersed into both hemispheres prior to evolving a fully aquatic lifestyle. Geochronologic constraints on the age of new Peruvian archaeocetes establish them as the oldest whales from South America and among the oldest known from the Southern Hemisphere, which highlights the need for better sampling of marginal marine rocks from this part of the world.