Adriana Cecilia Mancuso, Cecilia Andrea Benavente, Elena Previtera, Andrea Beatriz Arcucci & Randall B. Irmis (2017)
Carnivore coprolites from the lower Carnian (Upper Triassic) Chañares Formation, northwestern Argentina.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
Carnivore coprolites from the lower Carnian Chañares Formation
Potential preservation of carnivore and herbivore coprolites
Trophic links in the Chañares ecosystem
First report of a microvertebrate assemblage in Chañares Formation
A comprehensive protocol to assure that the structures are most likely coprolites
With high organic content and abundant microbiota, feces are typically only preserved for more than a couple of days, weeks or months after deposition and most never enter the fossil record. The range of depositional conditions favorable to the feces preservation is narrow, but depends on a large number of biotic and abiotic factors. Moreover, because the chemistry and microbiology of feces often promotes mineralization, discriminating between coprolites and some inorganic sedimentary structures is often difficult. We propose a protocol to identify coprolites in the fossil record that encompasses all the criteria previously defined. We then apply this protocol to identify putative coprolites from the lower Carnian (Upper Triassic) Chañares Formation of northwestern Argentina. Using a variety of analytical methods and several different criteria, we were able to identify them as carnivore coprolites. Based on extant analogs, the most probable producer would be a small carnivorous cynodont or archosauriforms, and the prey is likely a tiny therapsid or archosauriform. This is the first detail report of carnivore coprolites from this unit, and provides direct evidence of trophic links in the Chañares ecosystem.