Nevadella is an extinct genus of trilobites, fossil marine arthropods, with species of average size (about 5cm (02inches) long). It lived during the late Atdabanian stage, which lasted from 530 to 524 million years ago during the early part of the Cambrian Period.[1]
The name is derived from Nevadia, a related genus.
Nevadia predates Nevadella and may include its direct ancestor.
The body of Nevadella is very flat dorso-ventrally. The general outline of its thin, lightly calcified exoskeleton is inverted 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 wedging out slightly in the frontal half and with a rounded front (like the silhouette of a slim pawn). The glabella and the frontal margin almost or entirely touch (in jargon: the preglabellar field is short or absent). Cephalic margin at least as wide as the most frontal thoracal segment. The thorax has 17 to 23 segments, gradually diminishing in size. The pleural spines are long and sickle-shaped. The tailshield (or pygidium) is very small and subquadrate in shape.[2]
Fossils of Nevadella have been found in the late Atdabanian of the USA (California, Nevada) and Canada (Cordilleran region).
Contemporary taxa that also occur in the so-called "Nevadella" Zone include Esmeraldina, Holmiella, Palmettaspis, Bradyfallotaspis, Geraldinella, Paranevadella, Nevadia, Buenellus, and Cirquella.[2]
Nevadella species were probably marine bottom dwellers, like all Olenellina.