Amiskwia is a large Cambrian gnathiferan with complex gnathostomulid-like jaws

Jean-Bernard Caron, Brittany Cheung
2019 Communications Biology  
Phylogenomic studies have greatly improved our understanding of the animal tree of life but the relationships of many clades remain ambiguous. Here we show that the rare soft-bodied animal Amiskwia from the Cambrian of Canada and China, which has variously been considered a chaetognath, a nemertine, allied to molluscs, or a problematica, is related to gnathiferans. New specimens from the Burgess Shale (British Columbia, Canada) preserve a complex pharyngeal jaw apparatus composed of a pair of
more » ... ements with teeth most similar to gnathostomulids. Amiskwia demonstrates that primitive spiralians were large and unsegmented, had a coelom, and were probably active nekto-benthic scavengers or predators. Secondary simplification and miniaturisation events likely occurred in response to shifting ecologies and adaptations to specialised planktonic habitats.
doi:10.1038/s42003-019-0388-4 pmid:31924975 fatcat:a3nl6lgkhjgyreqb7bsabekazy