A review of Silurian discinoid brachiopods from historical British localities

Abstract

The present article revises descriptions of Silurian discinoid brachiopods by J.

A review of Silurian discinoid brachiopods from Gotland, Sweden

“…-Gotland shells referred to Acrosaccus cocksi Mergl, 2006 are indistinguishable from the British specimens from the Coalbrookdale Formation (Wenlock) except for the more regular concentric rugellae. The Gotland specimens are derived from the Slite (Sheinwodian), Halla (Homerian), and Hemse formations (Gorstian).…”

“…-The shell differs from A. cocksi Mergl, 2006 by having a planar valve and more densely packed rugellae, with narrower interspaces. In general morphology the dorsal valves are similar to dorsal valves of Emsian and Eifelian age of the Barrandian, referred by Mergl (2008) and Mergl & Ferrová (2009) to Acrosaccus Willard, 1928. Distribution.…”

“…The height, convexity, and ornamentation of the Gotland specimens are comparable with the shape of the early growth stages of the British specimens. The length of the pedicle track is also related to shell size (see Mergl 2006, fig. 6A, B).…”

“…Revision of Silurian discinoid brachiopods from the Barrandian (Mergl 2001) and from classical British localities (Mergl 2006) provided a sound foundation for a critical review of the material from Gotland.…”

“…Their drift along shelves of Laurussia towards docking Avalonia in Silurian can explain the close affinity of some Gotland and British species (Cocks & Torsvik 2005). Some British species [Acrosaccus cocksi Mergl, 2006, and Orbiculoidea forbesii (Davidson, 1848)] occur in Gotland, but other taxa appear to be endemic to Gotland (Acrosaccus barabackenis sp. nov., Acrosaccus hallaensis sp.…”