title: Abundance distributions imply elevated complexity of post-Paleozoic marine ecosystems.
abstract: Likelihood analyses of 1176 fossil assemblages of marine organisms from Phanerozoic (i.e., Cambrian to Recent) assemblages indicate a shift in typical relative-abundance distributions after the Paleozoic. Ecological theory associated with these abundance distributions implies that complex ecosystems are far more common among Meso-Cenozoic assemblages than among the Paleozoic assemblages that preceded them. This transition coincides not with any major change in the way fossils are preserved or collected but with a shift from communities dominated by sessile epifaunal suspension feeders to communities with elevated diversities of mobile and infaunal taxa. This suggests that the end-Permian extinction permanently altered prevailing marine ecosystem structure and precipitated high levels of ecological complexity and alpha diversity in the Meso-Cenozoic.
authors.affiliation: Department of Geology, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605, USA. pwagner@fmnh.org
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Wagner
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Kosnik
authors.forename: Scott
authors.initials: S
authors.lastname: Lidgard
mesh_terms: D000818:Animals; D044822:Biodiversity; D016208:Databases, Factual; D017753:Ecosystem; D053476:Extinction, Biological; D005580:Fossils; D007448:Invertebrates; D016013:Likelihood Functions; D008386:Marine Biology; D011156:Population Density