''Crepicephalus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

from a well-known class of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

marine

arthropod Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

s, the

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. It lived from 501 to 490 million years ago during the

Dresbachian The Dresbachian is a Maentwrogian regional stage of North America, lasting from 501 to 497 million years ago. It is part of the Upper Cambrian and is defined by four trilobite zones. It overlaps with the ICS-stages Guzhangian, Paibian and the lowe ...

faunal stage In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convent ...

of the late

Cambrian Period The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (m ...

Reassigned species

Some species, previously described as ''Crepicephalus'' have since been moved to other genera. * ''C. angusta'' = '' Kochaspis angusta'' * ''C. convexus'' = '' Crepicephalina convexa'' * ''C. liliana'' = '' Kochaspis liliana'' * ''C. nitidus'' = '' Dunderbergia nitida'' * ''C. quadrans'' = '' Ehmaniella quadrans'' * ''C. unca'' = '' Uncaspis unca''

References

Ptychopariida genera Cambrian trilobites Extinct animals of North America Paleozoic life of Newfoundland and Labrador Paleozoic life of the Northwest Territories Paleozoic life of Yukon {{Ptychopariida-stub