Large-Diameter Burrows of the Triassic Ischigualasto Basin, NW Argentina: Paleoecological and Paleoenvironmental Implications

Researchers have uncovered large-diameter ichnofossils in the Upper Triassic Ischigualasto and Los Colorados formations of northwestern Argentina, revealing early Mesozoic fossorial behavior. Three distinct morphotypes were identified: two likely constructed by tetrapods, given their tunnel networks, and a third with a complex, calcareous structure suggesting combined plant/animal interactions. These burrows, associated with fluvial overbank lithologies deposited under arid conditions, indicate that vertebrates used burrowing to cope with extreme seasonal or perpetual dryness during Pangean climates. Comparisons of burrow morphology with paleovertebrate fauna suggest small carnivorous cynodonts like Ecteninion or Probelesodon as possible architects for Morphotype 1, while the architect for Morphotype 2 remains uncertain due to size mismatches.

Colombi, C. E., Fernández, E., Currie, B. S., Alcober, O. A., Martínez, R., & Correa, G. (2012). Large-Diameter Burrows of the Triassic Ischigualasto Basin, NW Argentina: Paleoecological and Paleoenvironmental Implications. PLoS ONE, 7(12), e50662. https://doi.org/10.1371/journal.pone.0050662