Permian lyttoniid brachiopod Petasmaia from Akasaka, Mino Belt, central Japan

Abstract

A lyttoniid brachiopod species, Petasmaia expansa Cooper and Grant, 1969, is described from the middle member (Neoschwagerina margaritae Zone; upper Murgabian) of the Akasaka Limestone within the Mino Belt of central Japan. Petasmaia is a rare brachiopod genus, with the only two known species identified so far obtained from the Lower and Middle Permian of West Texas and from the Middle Permian of Akasaka. The presence of P. expansa in the Akasaka area suggests that reef-seamount complexes of the Mino Belt, including those within the Akasaka area, formed in a mid-Panthalassan equatorial region between the Palaeotethys and the North American continent in the Middle Permian.