Squalea
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Ray-like sharks such as the Atlantic angel shark ( Squatina dumeril ) have led to the assumption that rays are only a subgroup of squalomorphic sharks. |
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| Squalea | ||||||||||||
| Shirai , 1992 |
The Squalea are a taxon of the Neoselachii (modern sharks + rays) established in 1992 by the Japanese ichthyologist Shigeru Shirai , in which the ray-like shark groups (dogfish-like , Hexanchiformes , saw sharks and angel sharks ) and rays (Batoidae) were combined. About 800 species belong to the Squalea , the rays make up about three quarters of these species. In all Squalea, with the exception of the Hexanchiformes, the anal fin has not developed, as in most primitive cartilaginous fish. The Squalea live mainly on or near the seabed ( benthal ), often also in the deep sea.
Rays and saw sharks (Pristiophoriformes) have been considered sister groups since the morphological studies of the US shark expert Leonard Compagno in the 1970s . A gradual development of the rays from dogfish-like ancestors, which lost their anal fin, through the angel-shark and sawshark-like, to the fully developed rays with pectoral fins widened to the sides of the head, gills on the ventral side and a spiraculum that sucked in the respiratory water was assumed serves. The sharks would therefore be paraphyletic and thus only a form taxon , the rays only a subgroup of the squalomorphic sharks.
The following cladogram shows the rays as a sub-taxon of the squalomorphic sharks. Rays and the ray-like angel sharks and saw sharks, in which a tendency towards widening of the pectoral fins and the shifting of the gill slits to the belly side, are summarized as Hypnosqualea.
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In the meantime, however, there have been numerous molecular biological studies that, as previously assumed, confirm a basic dichotomy between sharks and rays. The morphological correspondences of the squalomorphic sharks with the rays then developed convergent .
Since the rays, like the modern sharks, can be traced back to the fossil record since the early Jurassic , an ancestry of the rays at the end of a long evolutionary line of the Squalea is not supported by paleontological data.
The taxon Squalomorphii , an alternative to the Squalea, includes dogfish-like , Hexanchiformes , saw sharks and angel sharks , excluding rays.
Individual evidence
- ↑ Shirai, Shigeru, 1992: Squalean Phylogeny, a new framework of "squaloid" sharks and related taxa . Hokkaido University Press, Sapporo, Japan, ISBN 4-8329-0276-8 .
- ↑ Deutsche Elasmobranchier-Gesellschaft: Revision of the Squaliformes systematics ( Memento of the original of September 28, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (German summary of Shirai's work)
- ^ A b Alfred Goldschmid: Chondrichthyes. Page 220 in: W. Westheide and R. Rieger: Special Zoology. Part 2. Vertebrate or skull animals. Spectrum, Munich 2004. ISBN 3-8274-0307-3
- ^ A b Joseph S. Nelson, Fishes of the World , John Wiley & Sons, 2006, ISBN 0-471-25031-7
- ↑ Christophe J. Douady, Miné Dosay, Mahmood S. Shivji & Michael J. Stanhop: Molecular phylogenetic evidence refuting the hypothesis of Batoidea (rays and skates) as derived sharks. Molecular Phylogenetics and Evolution, Volume 26, Issue 2, February 2003, Pages 215-221 doi : 10.1016 / S1055-7903 (02) 00333-0
- ↑ MP Heinicke, GJP Naylor, SB Hedges: Cartaginous fishes. in SB Hedges, S. Kumar: The Timetree of Life. Oxford University Press, USA, 2009, ISBN 9780199535033
- ↑ BA Humana, EP Owena, LJV Compagnob & EH Harleya: Testing morphologically based phylogenetic theories within the cartilaginous fishes with molecular data, with special reference to the catshark family (Chondrichthyes; Scyliorhinidae) and the interrelationships within them. Molecular Phylogenetics and Evolution, Volume 39, Issue 2, May 2006, pages 384-391, doi : 10.1016 / j.ympev.2005.09.009
- ↑ Jon. Mallatt, CJ Winchell: Ribosomal RNA genes and deuterostome phylogeny revisited: more cyclostomes, elasmobranchs, reptiles, and a brittle star. Molecular Phylogenetics and Evolution (2007), Volume: 43, Issue: 3, Pages 1005-1022, doi : 10.1016 / j.ympev.2006.11.023
- ^ John A. Musick & Julia K. Ellis: Reproductive Evolution of Chondrichthyans. in William C. Hamlett: Reproductive Biology and Phylogeny of Chondrichthyes Sharks, Batoids and Chimaeras. Science Publishers, US ISBN 1-57808-314-1 PDF
- ↑ GJP Naylor, YES Ryburn, O. & A. Lopez Fedrigo: Phylogenetic Relationships among the major lineages of. Modern Elasmobranchs. PDF ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ^ CJ Underwood: Diversification of the Neoselachii (Chondrichthyes) during the Jurassic and Cretaceous. Paleobiology, 32 (2) (2006). pp. 215-235. PDF
- ↑ Ximena Vélez-Zuazoa & Ingi Agnarsson: Shark tales: A molecular species-level phylogeny of sharks (Selachimorpha, Chondrichthyes). Molecular Phylogenetics and Evolution, Volume 58, Issue 2, February 2011, pages 207-217 doi : 10.1016 / j.ympev.2010.11.018
- ↑ CJ Winchell, AP Martin, J. Mallatt: Phylogeny of elasmobranchs based on LSU and SSU ribosomal RNA genes. Molecular Phylogenetics and Evolution, Volume 31, Issue 1, April 2004, Pages 214-224, doi : 10.1016 / j.ympev.2003.07.010 .
- ↑ Elasmo-research.org Galea and Squalea: Two Great Branches of Elasmobranch Evolution
- ^ CJ Underwood: Diversification of the Neoselachii (Chondrichthyes) during the Jurassic and Cretaceous. Paleobiology, 32 (2) (2006). pp. 215-235. PDF
