Cambrian Onychophora or Xenusians

The Cambrian xenusians have certain similarities to modern onychophorans and tardigrades, and it is tempting to suggest a relationship to one or the other of them. However, similarities are often on a fairly general level. For instance, the three groups all shed their cuticle, but they leave it in three different ways: through a ventral split, through a dorsal split, and through the anterior opening, respectively. Considering also all other characters, we are left with a complicated mosaic character pattern that is indeed difficult to interpret. In addition, the fossils show a great diversity, and there is disagreement on how to interpret some features of them. It seems premature to interpret xenusians as close relatives of any extant group. They may or may not be related: we should also remember the plain fact that an overwhelming majority of characters in organisms have evolved more than once.