Waptia fieldensis Walcott, a mandibulate arthropod from the middle Cambrian Burgess Shale

Abstract: Waptia fieldensis is one of the iconic animals of the middle Cambrian Burgess Shale (ca 508 Ma) from British Columbia, Canada, that had lacked a detailed description since its discovery at the very beginning of the 20th century by Charles Walcott. We present here the first in-depth exploration and three-dimensional reconstruction of this remarkable shrimp-like arthropod. We reveal details of its sensory organs (compound eyes, antennae), brain structure and appendages involved in locomotion, respiration (gill-like lamellae) and feeding (e.g. mandibles), with unprecedented accuracy. We also coded the morphological characters of Waptia into an extensive cladistic analysis that includes a large number of fossil and extant arthropods, the objective being to reconstruct its phylogeny and evolutionary relationships. Waptia shed light on the remote ancestry of mandibulates (crustaceans + insects + myriapods) and the origin of modern crustaceans. Source: .