Supplementary material from "Oldest record of monk seals from the North Pacific and biogeographic implications"

• Main Authors: Velez-Juarbe, Jorge, Valenzuela-Toro, Ana M.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Figshare 2019
• Subjects: Evolutionary Biology; FOS Biological sciences; 40308 Palaeontology incl. Palynology; FOS Earth and related environmental sciences; 60301 Animal Systematics and Taxonomy; 60310 Plant Systematics and Taxonomy; Pacific; North Atlantic
• Online Access: https://dx.doi.org/10.6084/m9.figshare.c.4479617; https://rs.figshare.com/collections/Supplementary_material_from_Oldest_record_of_monk_seals_from_the_North_Pacific_and_biogeographic_implications_/4479617

True seals (crown Phocidae) originated during the late Oligocene–early Miocene (approx. 27–20 Ma) in the North Atlantic/Mediterranean region, with later (middle Miocene, approx. 16–11 Ma) dispersal events to the South Atlantic and South Pacific. Contrasting with other pinnipeds, the fossil record of phocids from the North Pacific region is scarce and restricted to the Pleistocene. Here we present the oldest fossil record of crown phocids, monachines (monk seals), from the North Pacific region. The specimens were collected from the upper Monterey Formation in Southern California and are dated to 8.5–7.1 Ma, predating the previously oldest known record by at least 7 Ma. This record provides new insights into the early biogeographic history of phocids in the North Pacific and is consistent with a northward dispersal of monk seals (monachines), which has been recognized for other groups of marine mammals. Alternatively, this finding may correspond with a westward dispersal through the Central American Seaway of some ancestor of the Hawaiian monk seal. This record increases the taxonomic richness of the Monterey pinniped assemblage to five taxa, making it a fairly diverse fossil assemblage, but also constitutes the oldest record of sympatry among all three extant pinniped crown clades.