Basal Middle Cambrian short-stalked eocrinoids from the Kaili biota: Guizhou province, China

Abstract

Gogiid eocrinoids (Echinodermata) are the most abundant coelomate invertebrates in the Middle Cambrian (Taijiangian) Kaili Biota, Taijiang County, Guizhou Province, China. Both long- and short-stalked taxa are represented. The short-stalked Globoeocrinus globulus n. gen. and sp. has a globular theca, with well-developed sutural pores on all thecal plates in older mature specimens, short, thick stalk composed of small polygonal to rounded platelets, a large flattened attachment disc, and up to ten long, thin, helically coiled brachioles with tall, pointed cover plates. Some younger mature specimens have varying patches of non-pored plates that usually occur on the upper (probably) posterior portion of the theca. This species is over three times more abundant than the other co-occurring long-stalked gogiid Sinoeocrinus lui Zhao, Huang and Gong, 1994. Most specimens of G. globulus (ca. 80%) attach to acrotretid brachiopods, trilobite exuviae, or other skeletal remains. They are also capable of attaching directly to the seafloor.