2022/05/27 by Shuji Niko · 1 citation
Agricultural and Biological Sciences · Earth and Planetary Sciences · #Cephalopods and Marine Biology #Paleontology and Stratigraphy of Fossils #Marine Biology and Ecology Research
paper · doi:10.2517/pr200010
openalex publication_date 2022/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
The holotype of Iwakiella ichiroi Hatai, Kotaka and Noda, 1972, from the Permian Kashiwadaira Member of Northeast Japan is reexamined. Although previously placed within the Tentaculitoidea or retained in the Problematica, the possession of the septum and the spherical shape of the initial chamber suggest that this specimen belongs to sphaerorthoceratid orthocerid of the Cephalopoda. The present result confirms that the Tentaculitoidea probably became extinct near the Carboniferous – Permian boundary with Hidagaienites arcuatus Niko, 2000, as the latest representative.