''Cloacaspis'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of Olenid Ptychopariid

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 At ...

. It lived during the early part of the Arenig stage of the

Ordovician Period The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. The ...

, a

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 ...

which lasted from approximately 478 to 471 million years ago.

Richard Fortey Richard Alan Fortey FRS FRSL (born 15 February 1946 in London) is a British palaeontologist, natural historian, writer and television presenter, who served as president of the Geological Society of London for its bicentennial year of 2007. Ea ...

has proposed that these particular trilobites lived in anoxic regions of the ocean floor, and cultivated symbiotic, sulfur-metabolizing bacteria.

Etymology

The generic name is a compound word from Latin, "cloaca," meaning sewer, and from Greek, "aspis," meaning "shield." Thus, ''Cloacaspis'' translate as "sewer shield." In his book, Trilobite! Eyewitness to Evolution, Fortey, who first discovered the genus in Ordovician strata in Spitsbergen, explained that the rocks they were found in had a rank, sulfurous odor, reminding him of raw sewage.Fortey, Richard. Trilobite! Eyewitness to Evolution Random House Inc, 2001 p 69

References

Olenina Ptychopariida genera Early Ordovician trilobites of Europe Fossils of Norway Taxa named by Richard Fortey {{Ptychopariida-stub