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This content will become publicly available on May 1, 2026

Title: Rebuilding Earth’s first skeletal animals: the original morphology of Corumbella (Ediacaran, Brazil)
The evolutionary onset of animal biomineralization in the late Ediacaran (ca555–538 Ma) is marked by the global appearance of enigmatic tubular fossils with unresolved phylogenetic relationships. Among these,Corumbella wernerifrom the Tamengo Formation (Corumbá Group, Brazil) has been variously interpreted as affiliated with cnidarians or bilaterians. Using synchrotron imaging and machine learning, we analysed new specimens ofC. wernerito reconstruct their original skeletal organization. Our findings reveal thatCorumbella’s tubes were originally conico-cylindrical. Large individuals ofCorumbella, including less compacted specimens, and compression experiments with modern annelid tubes all indicate that previous reconstructions of a quadrate outline and midline features were misled by taphonomic artefacts. We also show that the wall ofCorumbellais composed of a single layer of ring-shaped elements. Unlike the fourfold symmetry of scyphozoans or the complex cataphract-like structures of Cambrian bilaterians (e.g. halkieriids, tommotiids and wiwaxiids),Corumbelladisplays structural similarities with other late Ediacaran corumbellomorphs, such asCostatubus. These taxa exhibit a distinctive barrel-on-barrel tube construction, with modular elements stacked on each other rather than nested. Our findings redefineCorumbella’s morphology and phylogenetic affinities, contributing to a broader understanding of early biomineralizing metazoans and their ecological roles in the Ediacaran biosphere.  more » « less
Award ID(s):
2242732
PAR ID:
10641461
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Publisher / Repository:
The Royal Society Publishing
Date Published:
Journal Name:
Royal Society Open Science
Volume:
12
Issue:
5
ISSN:
2054-5703
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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