| 词条 | Spurdog |
| 释义 |
| name = Spurdogs | fossil_range = {{fossil_range|83|0}} Campanian to Present[1] | image = Squalus_acanthias2.jpg | image_caption = Spiny dogfish (Squalus acanthias) | taxon = Squalus | authority = Linnaeus, 1758 }}Squalus is a genus of dogfish sharks in the family Squalidae. Commonly known as spurdogs, these sharks are characterized by smooth dorsal fin spines, teeth in upper and lower jaws similar in size, caudal peduncle with lateral keels; upper precaudal pit usually present, and caudal fin without subterminal notch. 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] 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. SpeciesCurrently, 29 recognized species are placed in this genus:
See also
References1. ^{{cite journal | last = Sepkoski | first = J.J.Jr | authorlink = | coauthors = | title = A Compendium of Fossil Marine Animal Genera | journal = Bulletins of American Paleontology | volume = 363 | issue = | pages = 1–560 | publisher = | location = | year = 2002 | url = http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class | doi = | id = }} {{Taxonbar|from=Q737224}}2. ^Wilga, C.D., Motta, P.J. & Sanford, C.P. (2007): Evolution and ecology of feeding in elasmobranchs. Integrative and Comparative Biology, 47 (1): 55-69. 3. ^1 2 3 4 Viana, S.T.d.F., Carvalho, M.R.d. & Gomes, U.L. (2016): Taxonomy and morphology of species of the genus Squalus Linnaeus, 1758 from the Southwestern Atlantic Ocean (Chondrichthyes: Squaliformes: Squalidae). Zootaxa, 4133 (1): 1-89. 2 : Squalus|Extant Campanian first appearances |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。