Data from: Phylogenetic response of naraoiid arthropods to early - middle Cambrian environmental change

The Cambrian Period, primarily known for animal life diversifying,
experienced global extinctions. Pulses of extinction in Cambrian Series 2
are exemplified by the disappearance of archaeocyath sponges and
olenelline and redlichiid trilobites. However, the effect of such
extinctions on outer shelf organisms, as typify Burgess Shale-type (BST)
deposits, remains relatively unknown. The phylogeny of naraoiid
arthropods, represented in BST deposits globally, has consequently been
reconstructed from either side of the Series 2–Miaolingian extinction
event to evaluate the response of offshore marine organisms to Cambrian
environmental perturbation. As soft anatomy is known for only a subset of
naraoiid species, exoskeletal morphology has proven important. Misszhouia
and Naraoia (Naraoia) are distinguished morphometrically by posterior
shield length/width and anterior shield length/posterior shield
length. Morphometry has also been used to strengthen the identification of
some cryptic naraoiid species and revise stratigraphic ranges. A revised
phylogeny for naraoiids reveals Misszhouia as a monophyletic subgenus, the
former genus Pseudonaraoia nests within Naraoia and is placed in synonymy,
and the systematic position and status of the Subfamily Liwiinae are
sensitive to character weighting. Ten species of Naraoiidae range through
the Series 2–Miaolingian boundary, all naraoiid lineages originating
during the main BST window. The persistence of outer shelf naraoiids
through the Series 2 extinctions suggests that deeper offshore marine
environments were resilient to extinction during periods of environmental
stress. This study therefore provides novel empirical support for the
asylum of BST communities, which may contribute to the taxonomic longevity
and widespread geographic distribution of taxa in these biotas.