Malformed trilobites from the Ordovician and Devonian

Abstract

<p>Trilobite malformations are often ascribed to failed predation and represent key evidence for Paleozoic arthropod predator–prey systems. A large number of malformed trilobites are known to Cambrian-aged deposits and have recently been discussed at length. Conversely, most post-Cambrian records are noted as anecdotal points within larger taxonomic works. To expand the consideration of post-Cambrian injured trilobites, we report two malformed <i>Ogygiocarella debuchii</i> specimens from the Middle Ordovician of Wales and a heavily malformed <i>Spiniscutellum umbelliferum</i> specimen from the Early Devonian of the Czech Republic. These specimens are considered to represent records of failed predation. In considering these specimens, we explore possible injury-making groups, in particular noting that <i>S. umbelliferum</i> was likely prey for multiple apex predators. Continued examination of injured trilobites represents the main direction for uncovering how this iconic group of biomineralised arthropods interacted with higher tropic levels within Paleozoic foodwebs.</p>