Cambrian trees are oriented and labeled trees which fulfill local conditions around each node generalizing the conditions for classical binary search trees. Based on the bijective correspondence between signed permutations and leveled Cambrian trees, we define the Cambrian Hopf algebra generalizing J.-L. Loday and M. Ronco’s algebra on binary trees. We describe combinatorially the products and ...

The Cambrian appearance of fossils representing diverse phyla has long inspired hypotheses about possible genetic or environmental catalysts of early animal evolution. Only recently, however, have data begun to emerge that can resolve the sequence of genetic and morphological innovations, environmental events, and ecological interactions that collectively shaped Cambrian evolution. Assembly of ...

. Figure 1. Cambrian lobopodian diversity. (A) Aysheaia pedunculata, middle Cambrian Burgess Shale (NMNH-83942). (B) Claws of Aysheaia pedunculata (NMNH-365608). (C) Hallucigenia sparsa, middle Cambrian Burgess Shale (NMNH198658; courtesy of M. Smith, University of Cambridge. Nature 523, 75–78). (D) Microdictyon sinicum, early Cambrian Chengjiang (ELRC-30060; courtesy of G. Edgecombe, Natural H...

Burgess Shale-type deposits are renowned for their exquisite preservation of soft-bodied organisms, representing a range of animal body plans that evolved during the Cambrian 'explosion'. However, the rarity of these fossil deposits makes it difficult to reconstruct the broader-scale distributions of their constituent organisms. By contrast, microscopic skeletal elements represent an extensive ...

Detrital zircon populations of the South Qiangtang terrane (SQT) provide vital information for reconstructing Tethyan evolution Tibetan Plateau but are obscured by undefined affiliation detrital samples and superimposition multiple tectonothermal events. We outlined SQT based on geological mapping collated Cambrian-Triassic to investigate representative populations. Although diachronous strata ...