Abstract
A small, brightly coloured brachiopod, Shimodaia pterygiota n. gen. and n. sp., presently restricted to waters of less than 100m depth off Shimoda, Izu Penninsula, and parts of Sagami Bay, Honshu, Japan, is described and illustrated. Previously mistaken for Frenulina sanguinolenta (Gmelin), S. pterygiota is shown to differ from all other known laqueid brachiopods in its unique combination of adult cardinalial and brachidial features. Investigation of the loop ontogeny of S. pterygiota reveals that, whereas juvenile axial, cucullate and annular loop phases are comparable to those in other laqueids, the adult phase is unusual in consisting of an incomplete annular phase resulting from resorption of the transverse band. Only one adult specimen from over 200 recovered to date shows resuturing of previously discrete (resorbed) ascending loop branches to form a conventional annular phase.
