Assessing Ecological Relationships Among Late Triassic Vertebrates in Petrified Forest National Park

Reconstructing ecological interactions among extinct vertebrates is complex as direct evidence of faunal interaction seldom preserves, the complexities of taphonomic modification must be parsed, and the potential for non-analogue paleoecologies assessed. Utilizing a combination of PAIRS analysis and NMDS (Non-metric Multidimensional Scaling) ordination, we investigate evidence for vertebrate faunal relationships within the Late Triassic (Adamanian and Revueltian biozones) of Petrified Forest National Park, assess the likelihood that these patterns have ecological rather than preservational drivers, and examine how identified potentially ecologically meaningful interactions may have been impacted by the Adamanian–Revueltian turnover event. Results infer hypothetical predator-prey relationships and indicate possible paleofauna structural stability across the Adamanian–Revueltian boundary. Findings also suggest a “mosaic” of vertebrate taxa interactions distributed along a semi-aquatic to terrestrial gradient rather than a series of segregated paleofaunas. The influence of taphonomic biases on the interpretation of faunal structure appears minimal.