 Hou and Bergström used the name Lamellipedia as a superclass to replace Trilobitomorpha that was originally erected at the subphylum level, which they considered inappropriate.Most Artiopods are broadly similar in morphology to trilobites, possessing a dorsoventrally compressed body, with a trunk composed of between 6 and 19—generally 10 to 12—articulated segments, most of which contain wide pleurae.These pleurae are absent in the posteriormost segment, which bears a pair of non-walking appendages, and may be absent in the two or three posteriormost segments in rare cases.