Data from: Multi-segmented arthropods from the middle Cambrian of British Columbia (Canada)

A new arthropod, Kootenichela deppi n. gen. n. sp., is described from the
Stanley Glacier exposure of the middle Cambrian (Series 3, Stage 5)
Stephen Formation in Kootenay National Park (British Columbia, Canada).
This taxon possesses a number of primitive arthropod features such as an
elongate, homonomous trunk (consisting of at least 29 segments), poorly
sclerotised trunk appendages, and large pedunculate eyes associated with
an anterior (ocular) sclerite. The cephalon encompasses a possible
antenna-like appendage and enlarged raptorial appendages with a bipartite
peduncle and three spinose distal podomeres, indicative of megacheiran
(“great-appendage” arthropod) affinities. The relationships of
megacheirans are controversial, with them generally considered as either
stem-euarthropods or a paraphyletic stem-lineage of chelicerates. An
extensive cladistic analysis resolved Kootenichela as sister-taxon to the
enigmatic Worthenella cambria from the middle Cambrian (Series 3, Stage
5), Burgess Shale Formation in Yoho National Park (British Columbia),
which is herein reinterpreted as a megacheiran arthropod. Based on their
sister-group relationship, both taxa were placed in the new family
Kootenichelidae, to which Pseudoiulia from the Chengjiang biota is also
tentatively assigned. All of these taxa possess an elongate,
multi-segmented body and subtriangular exopods. This family occupies a
basal position within a paraphyletic Megacheira, the immediate outgroup of
Euarthropoda (crown-group arthropods). The resultant topology indicates
that analyses that have resolved megacheirans as stem-chelicerates have
done so because they have rooted on inappropriate taxa, e.g.,
trilobitomorphs and marrellomorphs.