2018/03/14 by Annalisa Berta, Morgan Churchill, Robert W. Boessenecker · 2 citations
Environmental Science · Earth and Planetary Sciences · #Marine animal studies overview #Ichthyology and Marine Biology #Paleontology and Evolutionary Biology
paper · pdf · doi:10.1146/annurev-earth-082517-010009
openalex publication_date 2018/03/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
The oldest definitive pinniped fossils date from approximately 30.6–23 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic “enaliarctines” falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19–14 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages.