A reconstruction of the lophophore of Devonian rhynchonellids (Brachiopoda) by using X-Ray micro-CT

Abstract

The X-ray microtomographic study has revealed contrast inclusions (possibly iron compounds) in several shells of Devonian (Emsian–Famennian) rhynchonellids (Brachiopoda) from Transcaucasia. Judging by the location of inclusions, they may correspond to soft tissues of lophophores. The spire-shaped inclusion in the shell of the holotype of the Late Devonian Sharovaella mirabilis Pakhnevich, 2012 has typical features of spirolophe and is interpreted as a part of one of lophophore spires. This find suggests that in the Late Devonian the spirolophe already existed in rhynchonellids. The dorsoventrally directed spirolophous lophophore is an ancient conservative feature of the order Rhynchonellida.