An Atlas of Malformed Trilobites from North American Repositories Part 3: The Field Museum of Natural History

Examples of malformed trilobites are well documented in the fossil record. These specimens are critical for elucidating aspects of trilobite paleoecology, particularly in the context of developmental biology, predation, and pathologies. Ongoing efforts to catalog these malformations within paleontological collections have yielded significant insight into trilobite paleobiology, especially related to posttraumatic recovery and predator-prey interactions. For the third component of this atlas, we identified five examples of malformations across Cambrian (Ogygopsis klotzi, Paradoxides davidis) and Silurian (Glyptambon verrucosus, Lichas breviceps) species within the Field Museum of Natural History collection. These specimens show demonstrable evidence of traumatic injuries, unsuccessful predation, and pathological developments. We investigate the etiologies of these malformations and compare them to other examples of malformed trilobites. Finally, we consider the history of trilobite collections at the Field Museum, exploring the major changes in the collection since the museum was founded.