135-8 Assessing Ecological Relationships Among Late Triassic Vertebrates in Petrified Forest National Park

Session: Science and Stewardship of U.S. National Park Service Paleontological Resources

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Abstract:

Terrestrial vertebrate paleocommunities are difficult to fully understand and interpolate for a myriad of reasons (time-averaging issues, taphonomic bias, non-analogue ecosystems, etc.). While prior investigations have been conducted in order to reconstruct potential ecosystems within the Late Triassic, all have been primarily qualitative, utilizing functional morphology, inferred diet, and general occurrence patterns observed within the field to build hypothetical trophic structures. While some direct evidence of taxon interaction exists in the form of preserved bite marks, such evidence remains scarce within the fossil record. Exposures of the Chinle Formation within Petrified Forest National Park (PEFO) contain stratigraphic evidence of a localized faunal and floral extinction known as the Adamanian-Revueltian turnover event, which occurred ~215 MYA. As of yet, it has not been determined whether this turnover dismantled existing faunal structures in addition to impacting taxa diversity. Utilizing a combination of PAIRS analysis, NMDS ordination, and ANOSIM testing, we examine potential faunal relationships, identify possible broad-scale ecological patterns, and reconstruct hypothetical paleocommunities within the Adamanian and Revueltian faunachrons of PEFO through documented taxa co-occurrence. Preliminary stratigraphic results were all interpreted within conservative significance values, as well as tested in the context of taphonomic and time-averaging biases in order to ensure an accurate interpretation of potential relationships/community structures as ecological in origin. Findings highlight new potential faunal relationships between individual taxa, indicate high degrees of interaction between most taxa within both faunachron datasets, and suggest that the Adamanian-Revueltian turnover did not demolish existing Adamnanian paleocommunity structures, but instead left available niche space for Revueltian taxa to adapt into.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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