静岡県の上部鮮新統大日層から産出したハイエナイモガイの新亜種

概要

論文の詳細を見る
Rhizoconus hyaena kakegawaensis n. subsp. is described from the upper Pliocene Dainichi Formation in Shizuoka Prefecture, central Japan. This new subspecies differs from Rhizoconus hyaena hyaena (Hwass), which lives in India, Indonesia and the South China Sea north to Hong Kong, by having concave sutural ramps, a spiral keel just above the suture, and a more-angulate shoulder. In the features of its shoulder, it resembles Rhizoconus hyaena concolor (Sowerby II), now living in the Solomon Islands and Papua New Guinea, but differs from the latter subspecies by having a more-convex body whorl. Rhizoconus hyaena kakegawaensis n. subsp. is a northern subspecies and is derived from the R. hyaena stock that expanded its geographic distribution northward during the warm episode at about 2 Ma. Two known conid species, Cleobula figulina (Linnaeus) and Chelyconus fulmen (Reeve), occur together with the new conid subspecies and are also described in detail.
日本貝類学会の論文
1999-09-30