An obolellate brachiopod with soft-part preservation from the Early Cambrian Chengjiang fauna of China

Abstract

The obolellates represent a poorly understood group of the oldest known cosmopolitan calcareous rhynchonelliform brachiopods. They made their first appearance in the early Atdabanian and became extinct at the end of the Middle Cambrian. Consequently, any information concerning the soft anatomy of this ephemeral lineage of brachiopods has great phylogenetic significance. This is the first report on two specimens of an obolellate with fine preservation of soft parts including the pedicle, marginal setae and possible imprints of a spiral lophophore, recovered from the early Cambrian Chengjiang Konservat Lagerstätte of Kunming, southern China. The setae are thin and densely fringed along the shell margin. The stout pedicle is distinctly composed of densely stacked tabular bodies, lacking a central coelomic lumen; it emerges through a possible foramen, and slightly tapers posteriorly with the distal end attached to exoskeletons of other organisms.