{{Short description|Genus of trilobites}} {{Automatic taxobox | fossil_range = {{Fossil range|Middle Ordovician|Late Ordovician}} | image = Ceraurus plus baby, Late Ordovician, Trenton Group, Quebec, Canada - Houston Museum of Natural Science - DSC01562.JPG | image_caption = Fossil ''Ceraurus'' with baby. | taxon = Ceraurus | authority = Green, 1832 | subdivision_ranks = Species | subdivision = | type_species = }}
'''''Ceraurus''''' is a genus of cheirurid trilobite of the middle and, much more rarely, the upper Ordovician. They are commonly found in strata of the lower Great Lakes region. These trilobites have eleven thoracic segments, a very small pygidium and long genal and pygidial spines.
''Ceraurus'' is quite common in the Ordovician of upstate New York, south-central and south-eastern Ontario, and the St. Lawrence Valley in Quebec, as well as in the Canadian Arctic. It and similar genera range in size from less than quarter an inch to well over five inches. Similar genera of trilobites occur in the Ordovician outcrops of the Volkhov River, near St. Petersburg, Russia.
The taxonomy of the genus is problematic, as the many variations of eye placement, decoration patterns of pustules, and spine length call the genus' defining characteristics into question. ''Ceraurus'' may, in fact, be at least four genera: ''Ceraurus'' sensu stricto, and the genera, ''Gabriceraurus'', ''Bufoceraurus'' and ''Leviceraurus''.
== References == {{Commons category}} * Ludvigsen, Rolf, Fossils of Ontario: Part I: The Trilobites. Toronto: Royal Ontario Museum, 1983.[https://archive.org/stream/fossilsofontario01bolt/fossilsofontario01bolt_djvu.txt] {{Reflist}}
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Category:Cheiruridae Category:Phacopida genera Category:Extinct animals of North America Category:Ordovician trilobites of North America Category:Middle Ordovician first appearances Category:Late Ordovician extinctions Category:Bromide Formation Category:Paleozoic life of Ontario Category:Verulam Formation Category:Paleozoic life of British Columbia Category:Paleozoic life of the Northwest Territories Category:Paleozoic life of Nunavut Category:Paleozoic life of Quebec
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