thumbnail

Iapetonudus (N. gen.) and Iapetognathus Landing, unusual Earliest Ordovician multielement conodont taxa and their utility for biostratigraphy

Brigham Young University Geology Studies

By:
, , , , and

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time
  • Download citation as: RIS

Abstract

The Early Ordovician (Tremadocian) multielement conodont genus Iapetognathus is one of the oldest denticulate euconodont genera known. The ramiform-ramiform apparatus structure of Iapetognathus is not similar morphologically to other Late Cambrian to Earliest Ordovician denticulate multielement taxa, such as Eodentatus or Cordyloduts, because the major denticulate process has a lateral rather than a posterior orientation as it is in the other two examples. For this reason the genus is believed to have developed from the coniform-coniform apparatus Iapetonudus ibexensis (N.gen., n.sp.) through the development of the denticulate lateral processes. The two genera have a number of morphologic features in common and appear in stratigraphic succession. Iapetognathus aengensis (Lindstro??m) is redefined as a multielement taxon using topotype material and Ig. preaengensis Landing is placed in synonymy with it. Iapetognathus sprakersi, recently described by Landing in Landing and others (1996), is recognized as a multielement species and the new multielement species, Ig. fluctivagus, Ig. jilinensis and Ig. landingi n. spp. are described herein, based on type specimens from Utah (U.S.A.), Jilin (China) and Colorado (U.S.A.) respectively. Iapetonudus and Iapetognathus are important genera in defining the level of the Cambrian-Ordovician boundary. Iapetonudus is currently recognized only from Utah, Texas and Oklahoma, but Iapetognathus is cosmopolitan in its distribution.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Iapetonudus (N. gen.) and Iapetognathus Landing, unusual Earliest Ordovician multielement conodont taxa and their utility for biostratigraphy
Series title:
Brigham Young University Geology Studies
Volume
44
Year Published:
1999
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Brigham Young University Geology Studies
First page:
27
Last page:
55