Stable and radiogenic isotope analyses on shark teeth from the Early to the Middle Permian (Sakmarian–Roadian) of the southwestern USA

Jan Fischer, Jörg W. Schneider, John Paul M. Hodnett, David K. Elliott, Gary D. Johnson, Silke Voigt, Michael M. Joachimski, Marion Tichomirowa, Jens Götze

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


δ18OPvalues and87Sr/86Sr ratios were determined on disarticulated xenacanthiform, hybodontid and ctenacanthid shark tooth material from several Early Permian (Sakmarian–Kungurian) continental bone beds of northern Texas and southern Oklahoma as well as from the marine Middle Permian (Roadian) of northern Arizona. The δ18OPvalues derived from the teeth of bone beds are in the range of 17.6–23.5‰ VSMOW, and are mostly depleted in18O by 0.5–5‰ relative to proposed coeval marine δ18OPvalues. This indicates an adaptation to freshwater habitats on the Early Permian coastal plain by several sharks. Distinctly higher δ18OPvalues from two bone beds are attributed to significant evaporative enrichment in18O in flood plain ponds.87Sr/86Sr ratios of around 0.71077 are notably more radiogenic than87Sr/86Sr of contemporaneous seawater. In contrast, the isotopic composition of teeth from the marine Kaibab Formation is characterised by low δ18OPvalues in the range of 13.4–15.6‰ VSMOW while87Sr/86Sr ratios of around 0.70821 are closer to the Roadian seawater value. The distinctly depleted δ18OPvalues cannot be readily explained by fluvially affected freshening in a nearshore marine environment, so a diagenetic alteration of the Kaibab material seems to be more likely, excluding it from further interpretation.

Original languageEnglish (US)
Pages (from-to)710-727
Number of pages18
JournalHistorical Biology
Issue number6
StatePublished - Nov 1 2014


  • Early–Middle Permian
  • Kaibab Formation
  • bioapatite
  • bone beds
  • freshwater shark
  • oxygen isotopes
  • strontium isotopes

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences


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