Taxonomy, morphology, shell structure and early ontogeny of Pelmanotreta nom. nov. from the lower Cambrian of Siberia

Abstract

The new generic name Pelmanotreta is proposed under the provisions of the International Code of Zoological Nomenclature (ICZN) to replace Cryptotreta Pelman, 1977 (Brachiopoda), a junior homonym of Cryptotreta Blanc & Foote, 1961 (Arthropoda). This poorly known brachiopod genus and its type and only species, Pelmanotreta neguertchenensis (Pelman, 1977), from the early Cambrian of Siberia is redescribed. The family-level taxonomy of Pelmanotreta and other “cryptotretid” brachiopods is uncertain. In Pelmanotreta, dorsal valves vastly outnumber ventral valves in all collections but new specimens of the poorly known ventral valve reveal a possibly septate and poorly mineralized apical region. A prismatic hexagonal shell structure comparable to that of Salanygolina is described. P. neguertchenensis preserves the earliest known record of a larval shell in brachiopods.

Keywords::

• early Cambrian
• Brachiopoda
• Siberia
• systematics
• shell structure

Acknowledgements

John S. Peel (Uppsala) is thanked for financial and practical assistance. Timothy P. Topper (Uppsala) and Stefan Bengtson (Stockholm) are thanked for valuable discussions on brachiopod taxonomy and systematic nomenclature. Financial support from The Swedish Research Council (to Holmer, VR 2009-4395, 2012-1658, and through J.S. Peel) and the Russian Foundation of Basic Research (to Ushatinskaya, project 13-04-00322) is gratefully acknowledged.