Vertebrate paleontology

Abstract

The accumulations of bones and teeth in the deep "holes" within the Aucilla River provided the initial impetus for most of the SCUBA collecting in that river. In the dark-water settings typical of that river, especially during summer months, most of the material recovered consisted of large land mammal elements. For example, in his study of Bison evolution, Robertson (in Webb, 1974) relied heavily on Aucilla River collections of Bison antiquus skulls as the most extensive in Florida. It also became evident to both professional and amateur collectors that fully articulated skeletons were sometimes preserved in the river. Their occurrence was associated with incompletely eroded pockets of fine-grained, organic deposits encountered on the river bottom. The recovery of several mammoth and mastodon skeletons was reported by Webb (1976). The full skeleton of one large male Mammuthus now stands in the Florida Museum of Natural History next to a large male Mammut from another site in the Aucilla River. In retrospect it is evident that these early collecting efforts were too narrowly focused on trophy hunting. The skeletons were disassociated from any faunal, floral, or cultural context. And they were so efficiently recovered that they had limited stratigraphic or chronologic data. It is now evident that collectors in the Aucilla River ought to have distinguished at least the two major intervals of deposition, one in full glacial, and the other some 20,000 years later, in the late glacial. Of course, such additional rigor would have required far more investment of time and money, especially for field time and also for carbon dates. That is why two decades passed before a more rigorous scientific program to recover fossils in a broader multidisciplinary context could be mustered. In the present chapter we set forth the principal results regarding fossil vertebrates from the late Pleistocene levels at the Page-Ladson site. The primary evidence is presented as a comprehensive list of vertebrate taxa. We do not include the early Holocene vertebrates, as they are considered in a later section of this book. We also address three additional issues concerning these late Pleistocene vertebrates. One topic of vital importance is their paleoecology. This subject begins by separating the primarily aquatic fauna from the primarily terrestrial. We then briefly discuss each species (or next higher taxon) including its identification, ecology, and biogeography. We place special emphasis on the paleoecology of the terrestrial herbivores, especially their feeding habits. Once we have established the ecological roles of the terrestrial herbivores, we can more clearly explore the possible interactions of the first Floridians with the terrestrial vertebrate fauna. A final discussion features the impact of Page-Ladson data on the question of extinction of the late Pleistocene megafauna in North America. These same issues are taken up in other, supplementary ways in several of the following chapters on the late Pleistocene.