Pleurotomaria yokoyamai Hayasaka is a remarkably large gastropod commonly found in the middle Permian allochthonous Akasaka Limestone of central Japan. Its supraspecific systematics have however been unsettled. Examination of a museum collection and newly obtained material reveal previously unreported shell characteristics such as the presence of a long labral slit in the outer lip and a slit-like umbilicus surrounded by an accretionally growing callus pad. On the basis of these and previously known shell characters, a new genus Nipponomaria is proposed. We include Pleurotomaria? anatolica Enderle from the Permian anthracolithic limestone of northwestern Turkey as a member of this new genus.
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1 October 2016
Nipponomaria, a New Pleurotomarioidean Gastropod Genus (Mollusca) from the Permian Akasaka Limestone, Central Japan
Kaito Asato,
Tomoki Kase,
Teruo Ono,
Katsuo Sashida,
Sachiko Agematsu
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Paleontological Research
Vol. 20 • No. 4
October 2016
Vol. 20 • No. 4
October 2016
Akasaka Limestone
Gastropoda
Nipponomaria
Permian
systematics