2017/12/19 by Toshiyuki Kimura, Yoshikazu Hasegawa, Naoki Kohno · 1 citation
Environmental Science · Agricultural and Biological Sciences · #Marine animal studies overview #Ichthyology and Marine Biology #Cephalopods and Marine Biology
paper · doi:10.2517/2017pr007
openalex publication_date 2017/12/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/06/11
The family Eschrichtiidae is presently only represented by Eschrichtius robustus, a relict species from the North Pacific. Because of the scarcity of fossil records of the Eschrichtiidae, their evolutionary history is not well understood. A finely preserved mysticete skeleton was recovered from the Lower Pleistocene (1.77–1.95 Ma) of Tokyo, Japan, in 1961. The fossil consists of a cranium, mandibles, cervical, thoracic, lumbar and caudal vertebrae, chevrons, ribs, and forelimb bones, including scapula, humerus, radius, ulna and digit bones. Here, we describe and diagnose this fossil as a new species of the Eschrichtiidae, Eschrichtius akishimaensis sp. nov. This is the first fossil species of the genus Eschrichtius and suggests that at least two lineages represented by the modern species of Eschrichtius and the new species described here survived as late as the Early Pleistocene. This expands our knowledge of the paleodiversity of the eschrichtiids.