''Dykeius'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of large

shark Sharks are a group of elasmobranch cartilaginous fish characterized by a ribless endoskeleton, dermal denticles, five to seven gill slits on each side, and pectoral fins that are not fused to the head. Modern sharks are classified within the ...

in the family

Chlamydoselachidae Chlamydoselachidae is a family of primitive deep-sea sharks in the order Hexanchiformes. They are one of only two extant families in the order alongside the cow sharks in the family Hexanchidae, and the only members of the suborder Chlamydosela ...

. It contains a single known species, ''D. garethi'', from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Northumberland Formation The Northumberland Formation is a Late Cretaceous (?Campanian-?Maastrichtian)-aged geologic Formation (geology), formation in Canada. It belongs to the larger Nanaimo Group. Indeterminate bird and pterosaur fossils have been recovered from the for ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. The genus and species names honor paleontologist Gareth J. Dyke. It was a gigantic relative of the modern

frilled shark The frilled shark (''Chlamydoselachus anguineus''), also known as the lizard shark, is one of the two extant taxon, extant species of shark in the family (biology), family Chlamydoselachidae (the other is the southern African frilled shark, ''Ch ...

(genus ''

Chlamydoselachus ''Chlamydoselachus'' is a genus of sharks and the sole extant member of the family Chlamydoselachidae, in the order Hexanchiformes. It contains two extant and four extinct species. The most widely known species still surviving is the frilled sha ...

''). The teeth are much larger than those of any other known chlamydoselachid species, and comparison with modern frilled sharks estimates a total body size of at least . As with modern frilled sharks, it appears to have inhabited a deepwater environment. It is one of several giant frilled sharks known from the Late Cretaceous, along with '' Rolfodon goliath'' and undescribed taxa known from teeth, suggesting that such large sharks were not uncommon. It may have been specialized to hunt large cephalopods such as certain

belemnites Belemnites may refer to: *Belemnitida, an extinct order of cephalopods commonly known as "belemnites" *Belemnites (genus), ''Belemnites'' (genus), a belemnite genus from the Early Jurassic {{disambiguation ...

and

ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

, and eventually went extinct due to the disappearance of its prey.

References

{{Taxonbar, from=Q123685455, from2=Q133352573 Chlamydoselachidae Prehistoric shark genera Fossils of British Columbia Fossil taxa described in 2019 Monotypic prehistoric cartilaginous fish genera