Middle Ordovician (middle Darriwilian) Archaeospicularia and Entactinaria (radiolarians) from the Table Cove Formation, Piccadilly Quarry, Newfoundland, Canada

Sarah Kachovich,Jonathan C. Aitchison

doi:10.1017/jpa.2021.18

Abstract

AbstractNew, distinctive, well-preserved and previously undescribed constituents of a Middle Ordovician (middle Darriwilian, Dw2) radiolarian assemblage from the Table Cove Formation in Newfoundland are described. Three-dimensional X-ray micro-computed tomography (μ-CT) facilitates detailed examination of key specimens revealing hitherto unknown details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has previously impeded resolution of higher taxonomic rankings.Twenty-seven archaeospiculid and entactinarian taxa are described and illustrated including six new species: Westernbrookia polygonata n. sp., Neopalaeospiculum piccadilliensis n. sp., Ramuspiculum laxum n. sp. Spongentactinia nazarovi n. sp., Aspiculum irregulare n. sp., and Nyfrieslandia ramosissima n. sp. The investigation extends the known ranges of the species: Pararcheoentactinia reedae Won and Iams, 2002; Sphaeroentactinia robusta Won and Iams, 2015; Varispiculum ectospiculatum Won and Iams, 2015; and Svalbardospiculum multifurcatum (Won, Iams, and Reed, 2005), together with the genus Echidnina to the mid-Darriwilian.UUID: http://zoobank.org/74826b7b-bb86-45d5-ad23-e6e65e0706df.

Highlights

In order to fully document a well-preserved radiolarian fauna from the middle Darriwilian Table Cove Formation in Newfoundland, this paper is intended to complement earlier work of Kachovich and Aitchison (2020) that described spumellarian radiolarians from the same location
Radiolarian faunas have been reported from Ordovician strata globally from North and South America, Spitsbergen, Scotland, Russia, China, and Australia
Lower Paleozoic carbonates in Newfoundland are well known for numerous well-preserved radiolarian faunas from upper Cambrian to Lower Ordovician strata (Bergström, 1979; Aitchison et al, 1998; Zhang and Pratt, 2000; Won and Iams, 2002, 2011, 2013, 2015; Maletz and Bruton, 2005, 2007, 2008; Won et al, 2005; Maletz, 2007, 2011; Pouille et al, 2014a)

Summary

Introduction

In order to fully document a well-preserved radiolarian fauna from the middle Darriwilian Table Cove Formation in Newfoundland, this paper is intended to complement earlier work of Kachovich and Aitchison (2020) that described spumellarian radiolarians from the same location. It comprises part of an autochthonous Cambrian to Ordovician age passive margin carbonate shelf rift-drift assemblage that developed on the Laurentian margin during opening of the Iapetus Ocean (Williams and Hiscott, 1987; Torsvik et al, 1996; Lacombe et al, 2020). Middle Ordovician radiolarian biostratigraphy follows the work of Nazarov and Popov (1980), Nazarov (1988), Danelian and Popov (2003), Jones and Noble (2006), MacDonald (2006), Pouille et al (2013), and Aitchison et al (2017), and stratigraphic correlation for the radiolarians described is discussed elsewhere (Kachovich and Aitchison, 2020)

Materials and methods

Findings

Discussion