Deakin University
Browse

File(s) under permanent embargo

Permian spiriferellid brachiopods from northern Pangaea: taxonomy, biostratigraphy, macroevolution and implications for palaeoenvironmental and palaeobiogeographical reconstructions

journal contribution
posted on 2019-01-01, 00:00 authored by Sam Lee, Guang ShiGuang Shi, J Woo, T Y S Park, J R Oh, N K Kim, H A Nakrem, J I Tazawa
This study reports diverse spiriferellid brachiopods from the Permian rocks of Svalbard and adjacent areas (Arctic Canada and Subpolar Urals of Russia) located at the northern margin of Pangaea. In total, 11 brachiopod species in four genera are recognized and described in detail, including two new species (Spiriferella protodraschei and Arcullina? enokiani). According to our taxonomic investigation, morphological characteristics of the ventral sulcus and dorsal fold are relatively stable within each species, in spite of considerable intraspecific variations in shell outline and macro-ornamentation. In addition, both the arrangement of pustules, as a shell surface micro-ornamentation, and the development of delthyrial coverings are shown to be significant features for inferring phylogenetic relationships and for defining species. The best-known but still questionable taxon, Spiriferella keilhavii, is here identified as an endemic species restricted to Bjørnøya and, possibly, to central East Greenland; it is phylogenetically closest to S. loveni. Following the taxonomic revision, the stratigraphical ranges of the spiriferellids within the Kapp Starostin Formation in Spitsbergen are fully refined: three species, S. protodraschei, A. polaris and Timaniella wilczeki, are confined to the lowermost Vøringen Member (late Artinskian–early Kungurian), whereas S. loveni dominates the overlying members with a much longer stratigraphical range (late Kungurian–Lopingian?). This abrupt compositional change, along with comparable changes in other taxonomic groups, can be explained by a palaeoclimatic shift from cool to cold conditions between the Vøringen Member and the overlying Svenskeegga member. A similar biotic transition is identified between the Hambergfjellet and Miseryfjellet formations in Bjørnøya. On the other hand, S. loveni is abundant in the Late Permian strata of central East Greenland, but there it appears to be more costate in plication compared to its counterpart from Spitsbergen. It is suggested that this alteration in shell ornamentation may represent a possible response (adaptation) to warming arising from the southward migration of the species. http://zoobank.org/urn:lsid:zoobank.org:pub:85B863D2-DB42-4835-940A-2DE852C82178.

History

Journal

Journal of systematic palaeontology

Volume

17

Issue

22

Pagination

1871 - 1925

Publisher

Taylor & Francis

Location

Abingdon, Eng.

ISSN

1477-2019

eISSN

1478-0941

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2019, The Trustees of the Natural History Museum, London