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A model of reconstruction for the oral apparatus of the Ordovician conodont genus Protopanderodus Lindström, 1971

Author:
  • Johanna Mellgren
  • Mats Eriksson
Publishing year: 2006
Language: English
Pages: 97-112
Publication/Series: Transactions of the Royal Society of Edinburgh. Earth Sciences
Volume: 97
Document type: Journal article
Publisher: Royal Society of Edinburgh

Abstract english

Elements of the Ordovician conodont genus Protopanderodus have been investigated in order to provide a model of reconstruction for its oral apparatus. In total, 4202 elements from the five named species representing this genus in the Swedish Middle Ordovician are included in this study; P. rectus, P. parvibasis, P. graeai, P. robustus, and P. calceatus. The well-preserved specimens were studied in detail for identification of distinct element types and calculations were made to determine element ratios and minimum number of elements in a single apparatus. Three element groups, M, S and P, were recognized for all five species and their relative ratio is indicative of apparatuses consisting of at least 21 elements. The number of element types and their distribution, however, varies between the species. The four bicostate species, P. rectus, P. parvibasis, P. graeai, and P. robustus, have similar morphological characters and are believed to belong to the same evolutionary lineage. They possessed apparatuses consisting of M, Sa, Sb1, Sb2, Sc, Pa, and Pb elements. By contrast, the multicostate species P. calceatus is morphologically different and had an apparatus consisting of M1, M2, Sa, Sb, Sc, ”Sd”, Pa, Pb1, and Pb2 elements. These differences indicate that P. calceatus is not so closely related to the other species, possibly representing a separate evolutionary lineage, and may warrant an exclusive generic assignment.

Keywords

  • Geology
  • Sweden
  • conodonts
  • apparatus reconstruction
  • Protopanderodus
  • Ordovician

Other

Published
  • ISSN: 0263-5933
Mats Eriksson
E-mail: mats [dot] eriksson [at] geol [dot] lu [dot] se

Professor

Lithosphere and Biosphere Science

+46 46 222 96 02

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