Taxonomy and palaeoenvironmental distribution of palaeopascichnids

Palaeopascichnida is a problematic group of extinct organisms that is globally distributed in Ediacaran sequences of Avalonia, Baltica, Siberia, South China and Australia. The fossils related to Palaeopascichnida consist of serially or cluster-like arranged, millimetre- to centimetre-scale globular or allantoid chambers, which are characterized by substantial differences in preservation, leading to no consistent diagnosis for these organisms. Here we integrate morphometric variation, stratigraphic distribution and habitat settings of more than 1200 specimens from all known fossil localities. The results of the morphological analysis demonstrate variation in chamber shape and size, and allow us to recognize six valid species within the group. Statistical analysis of the specimen distribution with respect to sedimentary environments indicates a significant difference in palaeoecological settings between species, making a significant contribution to the evolution and systematic palaeontology of these problematic organisms and perspective on their use in Neoproterozoic biostratigraphy. Our revision and systematic study sheds new light on one of the least studied groups of the late Ediacaran biota.

Automated summary

This study provides a comprehensive analysis of the morphometric variation, stratigraphic distribution, and habitat settings of Palaeopascichnida, an extinct group of organisms from the late Ediacaran biota. Six valid species within the group were identified, and significant differences in paleoecological settings were found between species. This research contributes valuable insights into the evolution and systematic paleontology of these problematic organisms and their potential use in Neoproterozoic biostratigraphy.