Early Cambrian brachiopods and other shelly fossils from the basal Kinzers Formation of Pennsylvania

Abstract

An assemblage of seventeen species of Small Shelly Fossils, dominated by the brachiopod Eothele tubulus and species of the mollusk Yochelcionella, is described from the basal Kinzers Formation of Thomasville, Pennsylvania. The occurrence extends southwards the distribution of an Early Cambrian fauna (Cambrian Series 2, Stage 4) that is otherwise characteristic of the eastern shelf of Laurentia from New York to Greenland. The poorly known acrothelid brachiopod Eothele tubulus is redescribed based on large collections of ventral valves. The shell structure of E. tubulus is characterized by orthogonal baculae, and represents the oldest known example of a baculate shell structure, indicating that this type of shell structure evolved already in the Early Cambrian.