''Scapanorhynchus'' (from , 'shovel' and 'snout') is an extinct genus of shark belonging to the family Mitsukurinidae, that lived during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

period, from the

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

to the end of the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

. It is a close relative of the living

goblin shark The goblin shark (''Mitsukurina owstoni'') is a rare species of deep-sea shark. Sometimes called a "living fossil", it is the only extant representative of the family Mitsukurinidae, a lineage some 125 million years old. This pink-skinned ani ...

(''Mitsukurina owston''i), the only living member of the family. Later claimed record of ''Scapanorhynchus'', such as those from the

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

assigned to the species ''S. subulatus'', are highly dubious and may be misidentified sand sharks.Capetta, H., Chondrichthyes II, Mesozoic and Cenozoic Elasmobranchii, vol. 3B of Handbook of Paleoichthyology, Stuttgart, New York: Gustav Fischer Verlag, 1987.Glickman, L. S., and A. O. Averianov. "Evolution of the Cretaceous Lamnoid sharks of the genus Eostriatolamia." PALEONTOLOGICAL JOURNAL C/C OF PALEONTOLOGICHESKII ZHURNAL 32 (1998): 376-384

/ref> It was the first mitsukurinid to be described, with the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

(''S. lewisii'') being described nearly 10 years before the living goblin shark.

Description

''Scapanorhynchus'' had an elongated, albeit flattened snout and sharp awl-shaped

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

ideal for seizing fish, or tearing chunks of flesh from its prey. ''Scapanorhynchus'' normally did not exceed total length , although largest teeth with height about indicates upper total length of . Their extreme similarities to the living

, ''Mitsukurina owstoni'', lead some expertsMikko's Phylogeny Archive
/ref> to consider reclassifying it as ''Scapanorhynchus owstoni''. However, most shark specialists regard the goblin shark to be distinct enough from its prehistoric relatives to merit placement in its own genus.

Ecology

Unlike modern goblin sharks, which inhabit deep ocean waters and are sluggish opportunistic feeders that feed on benthic fish and invertebrates, ''Scapanorhynchus'' appears to have been a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

apex predator An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...

that inhabited the

epipelagic zone The photic zone (or euphotic zone, epipelagic zone, or sunlight zone) is the uppermost layer of a body of water that receives sunlight, allowing phytoplankton to perform photosynthesis. It undergoes a series of physical, chemical, and biological ...

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

. An isotopic analysis of its teeth suggests that it largely preyed on fish and occupied a high

trophic level The trophic level of an organism is the position it occupies in a food web. Within a food web, a food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the ...

in its ecosystem. It appears to have occupied a similar trophic level to ''

Squalicorax ''Squalicorax'', commonly known as the crow shark, is a genus of extinct lamniform shark known to have lived during the Cretaceous period. The genus had a global distribution in the Late Cretaceous epoch. Multiple species within this genus are co ...

'', another marine lamniform of the same habitat. Its active predatory lifestyle may have made it more susceptible to the ecological impacts of the Cretaceous-Paleogene extinction event, as with other sharks that had a similar lifestyle. Species of ''Scapanorhynchus'' may have occupied different habitats, with some like ''S. texanus'' inhabiting shallow marine environments like the

Western Interior Seaway The Western Interior Seaway (also called the Cretaceous Seaway, the Niobraran Sea, the North American Inland Sea, or the Western Interior Sea) was a large inland sea (geology), inland sea that existed roughly over the present-day Great Plains of ...

, while others like ''S. raphiodon'' may have inhabited deep marine environments, although it is also known from shallower environments. ''Scapanorhynchus'' has been found in shallow water rock deposits, such as those in

Hell Creek The Hell Creek Formation is an intensively studied division of mostly Upper Cretaceous and some lower Paleocene rocks in North America, named for exposures studied along Hell Creek, near Jordan, Montana. The formation stretches over portions o ...

, which appear to represent at least shoreline to brackish water conditions, and possibly even freshwater environments.

Description

Ecology

References

Further reading