''Komoksodon'' 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 hexanchiform

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 ...

known 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 ...

to the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

. It is the only member of the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Komoksodontidae. It is represented by a single known species, ''K. kwutchakuth'' from the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

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 ...

. However, teeth have also been identified from the Campanian of

Angola Angola, officially the Republic of Angola, is a country on the west-Central Africa, central coast of Southern Africa. It is the second-largest Portuguese-speaking world, Portuguese-speaking (Lusophone) country in both total area and List of c ...

and the m iddle Paleocene of

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, suggesting that ''Komoksodon'' briefly survived the Cretaceous-Paleogene extinction. All these localities appear to be deep-water habitats, suggesting that ''Komoksodon'' was a deep-water specialist much like other hexanchiforms. The New Zealand teeth were previously assigned to the orthacodontid '' Sphenodus'' before being reanalyzed prior to the genus's description, and likely represent an undescribed taxon due to certain morphological differences from the Canadian species. The teeth can be distinguished from all other extant and extinct sharks by their highly distinctive and complex root morphology, which suggests that teeth could closely interlock with one another. These structures are somewhat similar to those of chlamydoselachid sharks, suggesting that komoksodontids are also hexanchiforms. The genus name honors the

Kʼómoks The Kʼómoks or Kʼomoks, usually known in English as the Comox, are an Indigenous group of Coast Salishan-speaking people in Comox, British Columbia and in Toba Inlet and the Malaspina Peninsula areas of the British Columbia mainland across ...

people of

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

, who assisted with the naming of the species ''kwutchakuth'', which means "shark" in the unwritten

Comox language The Comox language () is a Coast Salish language historically spoken in the northern Georgia Strait region, spanning the east coast of Vancouver Island and the northern Sunshine Coast and adjoining inlets and islands. More specifically, was tra ...

References

{{Taxonbar, from=Q124115642, from2=Q133426077 Hexanchiformes Prehistoric shark genera Fossils of British Columbia Cretaceous sharks Paleocene sharks Fossil taxa described in 2019 Monotypic prehistoric cartilaginous fish genera