What is "zacanthoides"

Zacanthoides is an extinct Cambrian genus of trilobite. It was a nektobenthic predatory carnivore. Its remains have been found in Canada ( British Columbia, especially in the Burgess Shale, and Newfoundland), Greenland, Mexico, and the United States ( Alaska, Nevada, Utah, Vermont, and Idaho for which Z. idahoensis is named). Its major characteristics are a slender exoskeleton with 9 thoracic segments, pleurae with long spines, additional spines on the axial rings, and a pygidium that is considerably smaller than its cephalon.