MARINE ARTHROPOD LAGERSTÄTTEN: AN OVERVIEW IN HONOR OF RODNEY M. FELDMANN (Invited Presentation)

Arthropods have dominated all major animal clades, both in diversity and abundance, in the marine realm since the Cambrian, and in the terrestrial realm since about the Devonian-Carboniferous. Their fossil record, however, trifles compared to the records of other major groups that biomineralize more substantially or broadly. The tendency toward biomineralization in arthropods varies considerably, but arthropods seem underrepresented at both ends of the biomineralization spectrum. This is related, in part, to the “preservation paradox,” wherein the most abundant taxa in a living ecosystem are numerically underrepresented as fossils, related largely to non-biomineralization and predation. However, even among biomineralized forms, the discarding of incomplete material and underreporting of taxa contribute to a distorted perception of arthropod abundance and diversity in some deposits.

Rodney M. Feldmann is a name synonymous with our understanding of advances in marine arthropod paleobiology, advances in concepts that extend across all groups. Through careful documentation of arthropods from numerous lagerstätten and “ordinary” marine deposits, he, in collaboration with many students and colleagues, has weaved together a fascinating picture of the interrelationships among paleoecologic, taphonomic, and sedimentologic factors influencing our perception of the evolutionary history of Earth’s most diverse animal phylum. Insight into the paleobiology of arthropod clades commonly hinges on the discovery and documentation of taxa from either Konservat-lagerstätten or Konzentrat-lagerstätten, and Rod Feldmann has demonstrated the importance of studying both endmember types of deposits. Major Konservat-lagerstätten provide a counterbalance to the preservation paradox. Konzentrat-lagerstätten may provide a more realistic picture of original diversity and abundance but their full paleobiologic information potential is commonly underappreciated, especially when incomplete material is discarded or unreported. Incomplete specimens are in some instances the result of carnivorous activity, and recognition of this important paleoecologic-taphonomic facet, a persistent theme in Feldmann’s work, influences our perception of varied aspects of arthropod biology.