Sphenothallus Hall, 1847 from Cambrian of Skryje–Týřovice Basin (Barrandian area, Czech Republic)

Abstract

Two conical tubules from shales of the Skryje Member (Buchava Formation) at the Skryje–Luh and Týřovice–“Pod hruškou” localities, two of the key outcrops of this stratigraphic unit in the Skryje–Týřovice Basin (Barrandian area, Czech Republic), are described. One specimen consists of a small, compressed tubule with a very low expansion angle and wide and flat thickenings. The second, larger specimen exhibits indications of very narrow thickenings of a more abruptly expanding shell. Both specimens are assigned to the genus Sphenothallus Hall, but the latter only provisionally. Sphenothallus shows a worldwide distribution with numerous species, ranging from Cambrian to Permian in age. However, reported occurrences in the Cambrian are relatively sparse, in the form of rare specimens from the lower to middle Cambrian strata of Laurentia, Eastern Gondwana and Euro- pean peri-Gondwana. According to accepted palaeogeographical reconstructions, Cambrian Sphenothallus occurred in low as well as in higher palaeolatitudes.