Nevadia
Nevadia is an extinct genus of trilobites, fossil marine arthropods, with species of average size (about long). It lived during the Atdabanian stage, which lasted from 530 to 524 million years ago, in what are today Western Canada, the Western United States, and Mexico. Etymology. "Nevadia" is named for the US State of Nevada, where the first specimens of this genus where found. "N. fritzi" in named in honor of W.H. Fritz, a paleontologist who worked on olenelloid trilobites. Description. The body of "Nevadia" is very flat dorso-ventrally. The general outline of its thin, lightly calcified exoskeleton is  inverted wide drop-shaped. The front is rounded, widest at the back of the headshield (or cephalon), and tapering from there to an eventually rounded termination. The central area of the cephalon (or glabella) is distinctly tapered forward, sides slightly concave, but not wedging out in the frontal half and with a narrow rounded front. The glabella and the frontal margin do not touch (in jargon: the preglabellar field is present). Cephalic margin clearly less wide as the most frontal thoracal segment. The thorax has 27 segments. The segments look a bit degenerated behind the 15th to 18th (or an  opisthothorax can be distinguished). The pleural spines are long and sickle-shaped. The tailshield (or pygidium) is very small and subquadrate in shape. Taxonomic. "Nevadia" predates "Nevadella" and according to cladistic analysis includes its direct ancestor. Habitat. "Nevadia" species were probably marine bottom dwellers, like all Olenellina.