Migration of a Late Cretaceous fish

  • 0Paul H. Nelson Stable Isotope Laboratory, Department of Geoscience and Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa 52242-1379, USA. scott-j-carpenter@uiowa.edu

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Summary

This summary is machine-generated.

This study tracked the life history of Vorhisia vulpes, an ancient fish, using otolith isotopes. Vorhisia vulpes lived in brackish and marine waters, migrating seasonally and indicating a stable 18°C temperature.

Area Of Science

  • Paleontology
  • Paleoclimatology
  • Isotope Geochemistry

Background

  • Late Cretaceous sediments offer insights into climate change before the Cretaceous/Tertiary boundary.
  • Fossils from the Western Interior of North America provide crucial climate proxies.

Purpose Of The Study

  • To reconstruct the ontogenetic history of the Maastrichtian fish Vorhisia vulpes.
  • To utilize isotope ratios from otoliths to understand fish life history and paleoenvironment.

Main Methods

  • Analysis of carbon, oxygen, and strontium isotope ratios.
  • Examination of four aragonite otoliths from Vorhisia vulpes fossils.
  • Dating of fossils from the Fox Hills Formation, South Dakota.

Main Results

  • Vorhisia vulpes individuals hatched in brackish water (70-80% seawater).
  • They migrated to the Western Interior Seaway, staying for approximately 3 years.
  • Otolith isotopes indicate a mean seawater temperature of 18°C during their marine phase.

Conclusions

  • Vorhisia vulpes exhibited a complex life cycle involving migration between estuarine and marine environments.
  • The reconstructed temperature aligns with other paleoclimate indicators for the latest Maastrichtian.
  • This study enhances understanding of fish paleoecology and Late Cretaceous climate dynamics.

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