Spurdog

"Squalus" redirects here. For the submarine called Squalus, see USS Sailfish (SS-192).
Spurdogs
Temporal range: Campanian to Present

[1]

Squalus acanthias
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Squaliformes
Family: Squalidae
Genus: Squalus
Linnaeus, 1758

Squalus is a large genus of dogfish sharks, one of two genera in the family Squalidae. Commonly known as spurdogs, these sharks are characterized by smooth dorsal fin spines, teeth in their upper and lower jaws similar in size, a caudal peduncle with lateral keels; an upper precaudal pit is usually present, and the caudal fin is without a subterminal notch.

The name comes from squalus, the Latin for shark; this word is the root for numerous words related to sharks such as squaline, and scientific names for sharks, such as the order Squaliformes.

Jaw protrusion

In spurdogs, the hyomandibula (the bone connecting the braincase to the jaws) is oriented at a right angle to the neurocranium, while in other sharks, the hyomandibula runs more parallel to the body. This led some to think that the upper jaw of Squalus would not be as protractile as the jaws of other sharks. However, a study that compared different jaw suspension types in sharks showed that this is not the case and that Squalus is quite capable of protruding its upper jaw during feeding.[2]

Species

The 26 recognized species in this genus are:

See also

References

  1. Sepkoski, J. (2002). "A compendium of fossil marine animal genera (Chondrichthyes entry)". Bulletins of American Paleontology 364: 560.
  2. Wilga, Cheryl D., Philip J. Motta, and Christopher P. Sanford. "Evolution and ecology of feeding in elasmobranchs." Integrative and Comparative Biology47.1 (2007): 55-69.
  3. Naylor, G.J.P.; Caira, J.N.; Jensen, K.; Rosana, K.A.M.; White, W.T.; Last, P.R. (2012). "A DNA sequence–based approach to the identification of shark and ray species and its implications for global elasmobranch diversity and parasitology". Bulletin of the American Museum of Natural History 367: 1–262. doi:10.1206/754.1.
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