An Edgewood-type Hirnantian fauna from the Mackenzie Mountains, northwestern margin of Laurentia

Jin, Jisuo; Harper, David A.T.

Abstract

Silicified brachiopods from Hirnantian strata in three sections of the lower Whittaker Formation, Mackenzie Mountains, northwestern Canada, yielded a moderately diverse, Edgewood-type Hirnantian fauna, consisting of 13 species: Biparetis paucirugosus, Brevilamnulella laevis, Dalmanella edgewoodensis, Drabovia noixella, Eospirigerina putilla, Epitomyonia paucitropida, Epitomyonia sekwiensis, Glyptorthis papillosa new species, Gnamptorhynchos orbiculoidea, Katastrophomena mackenzii new species, K. parvicardinis, Parastrophina cf. P. minor, and Skenidioides sp. Compared to the typical Edgewood fauna of the American Midcontinent, Brevilamnulella laevis has a notably smaller shell than B. thebesensis, and is interpreted as a deeper-water form. The strong faunal affinity of the Mackenzie Mountains fauna to the Edgewood-type Hirnantian fauna is indicated by the occurrence of Biparetis, Brevilamnulella, Eospirigerina, and Gnamptorhynchos. In addition to the Edgewood type area within Laurentia, Biparetis, Eospirigerina, and Gnamptorhynchos are characteristic taxa that also occur in the Ellis Bay Formation (Hirnantian) of Anticosti Island. Multivariate and network analyses strongly support the differentiation between an Edgewood-type Hirnantian fauna in Laurentia and peri-Laurentia and the typical Hirnantia fauna of the Kosov Province in Gondwana, peri-Gondwana, South China, Kazakhstan terranes, Avalonia, and Baltica.

Citation

Jin, J., & Harper, D. A. (2024). An Edgewood-type Hirnantian fauna from the Mackenzie Mountains, northwestern margin of Laurentia. Journal of Paleontology, 98(1), 13-39. https://doi.org/10.1017/jpa.2023.87

• Journal Article Type: Article
• Acceptance Date: Jan 23, 2024
• Online Publication Date: Feb 27, 2024
• Publication Date: Feb 27, 2024
• Deposit Date: May 22, 2024
• Publicly Available Date: May 22, 2024
• Journal: Journal of Paleontology
• Print ISSN: 0022-3360
• Electronic ISSN: 1937-2337
• Publisher: Cambridge University Press
• Peer Reviewed: Peer Reviewed
• Volume: 98
• Issue: 1
• Pages: 13-39
• DOI: https://doi.org/10.1017/jpa.2023.87
• Public URL: https://durham-repository.worktribe.com/output/2456375