''Ceratiocaris'' is a

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 ...

paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

phyllocarid Phyllocarida is a subclass of crustaceans, comprising the extant order Leptostraca and the extinct orders Hymenostraca and Archaeostraca. See also *''Ceratiocaris'' *''Cinerocaris'' *''Vladicaris ''Vladicaris'' is an arthropod known from the ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s whose fossils are found in marine strata from the Upper

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

until the genus' extinction during the

Silurian The Silurian ( ) is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the shortest period of the Paleozo ...

. They are typified by eight short

thoracic 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 crea ...

segments, seven longer

abdominal The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

somite The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryonic stage of somitogenesis, along the head-to-tail axis in segmented animals. In vertebrates, somites subdivide in ...

s and an elongated pretelson somite. Their

carapace A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

is slightly oval shaped; they have many ridges parallel to the

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...

margin and possess a horn at the anterior end. They are well known from the

Eramosa The Eramosa is a Silurian stratigraphic unit exposed along the Niagara Escarpment in Ontario and western New York State. In the late nineteenth century it was an important source of building stone in Hamilton, Ancaster and Waterdown, and in th ...

formation of

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. The following species are included: *''Ceratiocaris bohemica'' Barrande, 1872 *''Ceratiocaris harpago'' Poschmann, Bergmann & Kühl, 2018 *''Ceratiocaris macroura'' Collette & Rudkin, 2010 *''Ceratiocaris monroei'' Salter ''in'' Murchison, 1859 *''Ceratiocaris murchisoni'' Jones & Woodward, 1888 *''Ceratiocaris papilio'' Salter ''in'' Murchison, 1859 *''Ceratiocaris pusilla'' Matthew, 1889 *''Ceratiocaris solenoides '' M'Coy, 1849 *''Ceratiocaris winneshiekensis'' Briggs ''et al.'', 2016

References

Prehistoric Malacostraca Prehistoric crustacean genera Ordovician arthropods Silurian animals Fossils of Canada Paleontology in Ontario Bertie Formation Paleozoic life of New Brunswick {{paleo-crustacean-stub