Over 100 well-preserved dissociated ophiuroid arm ossicles, i.e., lateral arm plates, dorsal arm plates, ventral arm plates, vertebrae and arm spines, were recovered from the upper Pleistocene Kioroshi Formation in the core of borehole GS-NY-1 at Nagareyama, Chiba Prefecture, central Japan. Following comparison with the lateral arm plates of ten extant amphiurid species occurring in the seas around Japan and with previously published fossil taxa in this family, the ossicles from Nagareyama were identified as belonging to the extant species, Amphiura multispina. This is the first fossil record of this form and the stratigraphically youngest of the Amphiuridae. The taphonomy and paleoenvironment of the brittle star fossils described are also discussed.
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4 January 2023
Amphiura multispina (Ophiuroidea, Amphiuridae) from the Upper Pleistocene Kioroshi Formation in a Drill Core at Nagareyama, Chiba, Central Japan
Yoshiaki Ishida,
Minoru Kaneko,
Asaka Yokobori,
Rin Mita,
Hiroyuki Ishikawa,
Ben Thuy,
Lea D. Numberger-Thuy,
Toshihiko Fujita
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Paleontological Research
Vol. 27 • No. 3
July 2023
Vol. 27 • No. 3
July 2023
extant species
lateral arm plate
ophiuroid
ossicle
paleoenvironment
taphonomy
