A new genus, Geniculigypa, and a new subfamily, the Geniculigypinae, are established. Both taxa are monotypic and have as their type species, Sieberella newtonensis Imbrie, 1959, from the Newton Creek Limestone (early Givetian) of Michigan. This species dramatically differs from all other known gypiduloid species in its possession of a prominent geniculation in both valves and by its radially grooved micro-ornament.

You do not currently have access to this article.