Discovery of bilaterian-type through-guts in cloudinomorphs from the terminal Ediacaran Period.

ABSTRACT: The fossil record of the terminal Ediacaran Period is typified by the iconic index fossil Cloudina and its relatives. These tube-dwellers are presumed to be primitive metazoans, but resolving their phylogenetic identity has remained a point of contention. The root of the problem is a lack of diagnostic features; that is, phylogenetic interpretations have largely centered on the only available source of information-their external tubes. Here, using tomographic analyses of fossils from the Wood Canyon Formation (Nevada, USA), we report evidence of recognizable soft tissues within their external tubes. Although alternative interpretations are plausible, these internal cylindrical structures may be most appropriately interpreted as digestive tracts, which would be, to date, the earliest-known

SUBMITTER: Schiffbauer JD 

PROVIDER: S-EPMC6954273 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature