A new cloudinid fossil assemblage from the terminal Ediacaran of Nevada, USA

Abstract

Owing to their temporal position during the decline of the classic Ediacara biota and the appearance of the more recognizable metazoans of the Cambrian Period, the terminal Ediacaran (∼551–539 Ma) assemblages of tubular fossil forms hold potential to improve understanding of biotic turnover near the end of the Ediacaran Period. Cloudinid taxa, including the terminal Ediacaran index fossil Cloudina, are the most well studied of these Ediacaran tubular forms due to their global palaeogeographical distribution. Recent reports revealed ecosystems of tubicolous organisms from the Great Basin region, Nevada, USA, and assigned taxa to such genera as Conotubus, Gaojiashania and Wutubus, well known from contemporaneous Chinese deposits. Appreciating the role that these organisms may have played in the evolutionary history of metazoans and recognizing their potential global distribution, however, requires careful taxonomic study. Here, we detail pyritized fossils from the Deep Spring and Wood Canyon formations of Esmeralda and Nye counties, Nevada, USA, respectively. Our investigation focused on the most abundant tubular taxon from the Nevada sites, which was previously generically assigned to Conotubus. While outwardly similar in morphology to this Gaojiashan taxon, our investigation determines that those fossils previously figured as Conotubus are instead two distinct taxa. The first represents a new species of Saarina – Saarina hagadorni sp. nov. – a genus previously known only from the East European platform, and the second is established as a novel genus and species, Costatubus bibendi gen. et sp. nov.

http://zoobank.org/urn:lsid:zoobank.org:pub:CC391194-FF96-4BDF-B9B2-E4361DA64A5B

Keywords:

• Nevada
• Ediacaran
• tubular fossils
• cloudinids
• Saarina
• Costatubus

Acknowledgements

The authors wish to thank the members of the Ediacaran Subcommission of the International Commission on Stratigraphy for their useful discussion and assistance in the field; and also acknowledge Elena Golubkova (Institute of Precambrian Geology and Geochronology Russian Academy of Sciences) for providing new photographs of Saarina juliae and Saarina kirsanovi holotypes. TS, JDS, SMJ and JWH acknowledge the financial support of the University of Missouri College of Arts & Science Dean’s Office and the John Roy Barker and Mary Smith Barker Faculty Enhancement Fund. JDS, BDA and CAT are supported by the National Science Foundation EAR CAREER-1652351; JDS and TS are supported by EAR/IF-1636643. EFS was supported by the Smithsonian Institution Peter Buck Fellowship, the Palaeontological Society Research Grant-PA-RG201703, and the NASA Astrobiology Institute Lewis and Clark Fund for Exploration and Field Research in Astrobiology. MAS would like to thank Jeremy Strange, Nate Strange and Greg Parsegov for assistance collecting at Mount Dunfee. NB is supported by the Russian Science Foundation (RSF #17-17-01241). BY is supported by the National Natural Science Foundation of China (No. 41502020). YC is supported by the Strategic Priority Research Program of Chinese Academy of Sciences (No. umc-XDB26010104). Fossils were collected under Paleontological Resources Use Permit No. N-94103, Bureau of Land Management, Nevada State Office.

Associate Editor: Ken Johnson