title: A merciful death for the "earliest bilaterian," Vernanimalcula.
abstract: Fossils described as Vernanimalcula guizhouena, from the nearly 600 million-year-old Doushantuo Formation in South China, have been interpreted as the remains of bilaterian animals. As such they would represent the oldest putative record of bilaterian animals in Earth history, and they have been invoked in debate over this formative episode of early animal evolution. However, this interpretation is fallacious. We review the evidential basis of the biological interpretation of Vernanimalcula, concluding that the structures key to animal identity are effects of mineralization that do not represent biological tissues, and, furthermore, that it is not possible to derive its anatomical reconstruction on the basis of the available evidence. There is no evidential basis for interpreting Vernanimalcula as an animal, let alone a bilaterian. The conclusions of evolutionary studies that have relied upon the bilaterian interpretation of Vernanimalcula must be called into question.
authors.affiliation: Department of Palaeozoology and Nordic Center for Earth Evolution, Swedish Museum of Natural History, Box 50007, SE-104 05, Stockholm, Sweden. stefan.bengtson@nrm.se
authors.forename: Stefan
authors.initials: S
authors.lastname: Bengtson
authors.forename: John A
authors.initials: JA
authors.lastname: Cunningham
authors.forename: Chongyu
authors.initials: C
authors.lastname: Yin
authors.forename: Philip C J
authors.initials: PC
authors.lastname: Donoghue
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002681:China; D005580:Fossils; D007448:Invertebrates / Q000033:anatomy & histology*