The Nepeidae are a family of

trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the ...

s, that lived during the late Middle Cambrian - earliest Upper Cambrian in what are today Australia, Antarctica, China and New Zealand. The Nepeidae can be recognized by a vaulted area between the front of the glabella and the frontal border, eye ridges that extend outward and slightly forward from the front of the glabella, and fixed cheeks that cut into the free cheeks at the inside of the eye, and that extend backwards, forming the inner base of the genal spines. The genal spines, however, are part of the free cheeks and extend backward at least half the length of the thorax. The

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...

has at least 20 segments. The tail shield (or

pygidium The pygidium (plural pygidia) is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. In groups other than insects, it contains the anus and, in females, the ovipositor. It is compo ...

) is small.

References

Ptychoparioidea Trilobite families Cambrian trilobites Drumian Guzhangian Miaolingian first appearances Miaolingian extinctions {{Ptychopariida-stub