ENVIRONMENTAL DISTRIBUTION OF MESOZOIC PARAVIALIANS

The environmental distribution of prehistoric organisms has become a topic of importance to scientists in the past few decades. This seeks to answer questions of diversity, territorial competition, evolution, diet, and even extinction. The purpose of this study is to present the environmental distribution for Mesozoic fossil collections of paravialians. These were separated into two groups as part of this project, which was done to aid the comparison between dinosaurs versus the ancestors to our modern-day birds. The project sought to answer the following question: Do “Mesozoic Prehistoric Birds” and “Small Bird-like Dinosaurs” groups share similar paleoenvironments? For this, The Paleobiology Database (PBDB) was used due to the type of necessary data required for completion (taxonomic, geographical, and geological information for both groups). In some instances, some of the available information on certain taxa was vague or unavailable, and therefore it had to be retrieved and entered into the PBDB as part of the project itself.

A threshold in weight was set for all both groups with the goal of comparative precision. Patagopteryx, the largest Mesozoic Prehistoric Bird occurrence evaluated was found to be 1.43 kg in weight. The remaining genera (post threshold establishment) was then analyzed for geographical distribution. From this, matching clusters of collections and/or similar locations were marked and translated onto maps. Finally, the geologic formation, lithology, and depositional environment was gathered for each fossil collection via the PBDB and utilized for environmental distribution extrapolation.

The final environmental output presented a high concentration of lacustrine collections for both groups. The purpose of this project was to provide the environmental correlations between these two Mesozoic paravialian groups, which was achieved to a general degree. Putting aside all other extinction factors that took place at the end of the Mesozoic, this territorial competition within each geographically distributed environment, could have been a significant contribution to the eventual demise of these small bird-like dinosaurs (within these size parameters), and therefore potentially an important contributing factor to the then upcoming aerial domination of the birds of today.