New exceptionally preserved arthropod from the Furongian of Canada

Abstract Background Corcoraniidae is a rare and understudied family of lower Paleozoic euarthropods that are important for understanding early chelicerate evolution. However, the diversity, morphology, and distribution of this group remain poorly resolved, particularly during the late Cambrian. Results Here, we describe a new corcoraniid from the late Cambrian (Furongian) Rivière-du-Loup Formation of Quebec, Canada. The distinctive morphology of this specimen warrants erection of a new genus and species, Magnicornaspis garwoodi gen. et sp. nov. This new taxon expands the morphological disparity in Corcoraniidae and suggests that a shift in location of large cephalic spines arose within older members of the clade. The presence of a corcoraniid within the Rivière-du-Loup Formation provides a crucial data point within the “Furongian Gap” suggesting that perceived biodiversity declines may be an artifact of sampling bias rather than anoxia-driven extinction. Conclusions This material highlights the potential for exceptional soft-bodied preservation within deeper-water lithofacies and warrants renewed investigation of the Rivière-du-Loup Formation. The deposit has a high probability of representing a new Furongian Konservat-Lagerstätte that will present important insight into late Cambrian biodiversity and the evolutionary history of early arthropods.