Vetulicolians--are they deuterostomes? chordates?

A recent paper by Shu et al.(1) reinterprets the fossil Vetulicola and related forms, all from the Lower Cambrian, as basal deuterostomes, assigning them their own phylum, Vetulicolia. Their conclusion is based on the presence of structures resembling gill slits and a trunk-like region that shows evidence of segmentation. This report summarizes the fossil evidence for their interpretation and evaluates a possible alternative, that vetulicolians may instead be tunicate-like chordates. Implications for our understanding of the nature of the primitive deuterostome (and chordate) body plan are discussed. . Copyright 2002 Wiley Periodicals, Inc