Cambrian Sphenothallus from Guizhou Province, China: early sessile predators

Abstract

Two species of Sphenothallus (Cnidaria) from Cambrian rocks of eastern Guizhou, China, are reported. One species, Sphenothallus songlinensis n. sp., from the Niutitang Biota (Lower Cambrian: Nangaoan Stage), represents the oldest reported example of the genus. Other specimens, referred to Sphenothallus taijiangensis?, are from the Kaili Formation (Lower Cambrian: Duyuanian Stage). The new material adds to the record of sessile cnidarians, an important group of predators, from the early part of the Cambrian. Occurrences of the genus in strata traditionally assigned to the Lower Cambrian show that Sphenothallus was among the earliest animals to produce a biomineralized (phosphatic) skeleton.