New insight into the soft anatomy and shell microstructures of early Cambrian orthothecids (Hyolitha).

ABSTRACT: Hyoliths (hyolithids and orthothecids) were one of the most successful early biomineralizing lophotrochozoans and were a key component of the Cambrian evolutionary fauna. However, the morphology, skeletogenesis and anatomy of earliest members of this enigmatic clade, as well as its relationship with other lophotrochozoan phyla remain contentious. Here, we present a new orthothecid, Longxiantheca mira gen. et sp. nov. preserved as part of secondarily phosphatized small shelly fossil assemblage from the lower Cambrian Xinji Formation of North China. Longxiantheca mira retains some ancestral traits of the clade with an undifferentiated disc-shaped operculum, a simple conical conch with apical septa and a two-layered microstructure of aragonitic fibrous bundles. The operculum int

SUBMITTER: Li L 

PROVIDER: S-EPMC7482263 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature