The oldest hyolithids (Cambrian Series 2, Montezuman Stage) from the Iapetan margin of Laurentia

John S Peel,Sebastian Willman,Steven J Hageman

doi:10.1017/jpa.2020.8

John S Peel, Sebastian Willman + Show 1 more

Open Access

https://doi.org/10.1017/jpa.2020.8

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Abstract

AbstractThe recent description of the nevadioid trilobiteBuenellus chilhoweensisWebster and Hageman, 2018 established the presence of early Cambrian Montezuman Stage (Cambrian Series 2, Stage 3) faunas in the Murray Shale of Chilhowee Mountain, Tennessee. The description recognized the oldest known age-diagnostic Cambrian trilobite from the Laurentian margin of the former Iapetus Ocean sinceBuenellusBlaker, 1988 is known otherwise only from the Sirius Passet Lagerstätte on the Innuitian margin of North Greenland. The bivalved arthropodsIsoxys chilhoweanusWalcott, 1890 andIndota tennesseensis(Resser, 1938a) have also been described from the Murray Shale, but hyolithids appear to be the dominant body fossils in terms of diversity and abundance. Although poorly preserved, the hyolithids occurring together withBuenellus chilhoweensisare described to improve understanding of the Murray Shale biota. The hyolith assemblages of the Murray Shale and Sirius Passet Lagerstätte are not closely similar, although the poor preservation of both hinders comparison.

Highlights

Outcrops of Laurentian lower Cambrian (Cambrian Series 2) strata extend from Alabama and Tennessee to North-East Greenland along the Eastern Seaboard of North America (Palmer, 1971; Hatcher et al, 1989; Williams, 1995; Derby et al, 2012; Torsvik and Cocks, 2016; Fig. 1)
This paper describes hyolithids that occur together with Buenellus chilhoweensis in the Murray Shale
The hyolithid assemblage is compared with the hyolith fauna occurring together with Buenellus higginsi Blaker, 1988 in the Sirius Passet Lagerstätte (Peel, 2010; Peel and Ineson, 2011) and other Montezuman–early Dyeran horizons in North Greenland (Peel and Willman, 2018)

Summary

Introduction

Outcrops of Laurentian lower Cambrian (Cambrian Series 2) strata extend from Alabama and Tennessee to North-East Greenland along the Eastern Seaboard of North America (Palmer, 1971; Hatcher et al, 1989; Williams, 1995; Derby et al, 2012; Torsvik and Cocks, 2016; Fig. 1). Buenellus is otherwise known only from its type locality in the Sirius Passet Lagerstätte (Fig. 1.1) of Peary Land, North Greenland (Blaker and Peel, 1997; Babcock and Peel, 2007; Ineson and Peel, 2011; Peel and Willman, 2018). The Sirius Passet Lagerstätte is the oldest known fossil assemblage within a succession of Montezuman–early Dyeran (Cambrian Stages 3–4) age assigned to the Buen Formation (Ineson and Peel, 1997; Peel and Willman, 2018; Fig. 1.3). The hyolithid assemblage is compared with the hyolith fauna occurring together with Buenellus higginsi Blaker, 1988 in the Sirius Passet Lagerstätte (Peel, 2010; Peel and Ineson, 2011) and other Montezuman–early Dyeran horizons in North Greenland (Peel and Willman, 2018)

Materials and methods

Systematic paleontology

Faunal comparison