Silurian Holmophyllidae (Rugosa) from the Gionyama Formation of the Kurosegawa Terrane, Southwest Japan

Three rugose species of the family Holmophyllidae Wang, 1947 are described for the first time from the Gionyama Formation of the Kurosegawa Terrane, Southwest Japan. They are Holmophyllum sp., Holmophyllum? sp., and Labechiellata reguloris (Sugiyama, 1939). These species are found in the Middle Member of the Gionyama Formation, which is Late Llandovery to Early Ludlow (Silurian) in age. Holmophyllum and Labechiellata are typical cosmopolitan genera. The compound holmophyllids such as Labechiellata may indicate tropical environments and suggest that ‘Proto-Japan’ was, like other areas that yield these corals, located in subtropical to tropical latitudes during the Silurian.