Rays

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Rays
Blue-spotted ray (Taeniura lymma)

Blaupunktrochen ( Taeniura lymma )

Systematics
Sub-stem : Vertebrates (vertebrata)
Superclass : Jaw mouths (Gnathostomata)
Class : Cartilaginous fish (Chondrichthyes)
Subclass : Euselachii
Subclass : Plate gill (Elasmobranchii)
without rank: Rays
Scientific name
Batoidea

Ray (Batoidea, Syn .: Rajomorphii) is a parent in the class of cartilaginous fish . With around 630 species , they represent more than half of the around 1170 species of cartilaginous fish.

Rays live in all seas worldwide, some species also in the deep sea . Real rays (Rajidae) and electric rays are more species-rich in marine areas of the temperate latitudes , the other families in tropical regions. Few species of the stingray family (Dasyatidae) also live in brackish and fresh water . In South America , with two exceptions , the Potamotrygonidae live in the major streams and rivers of the continent.

In the North Sea , especially members of the Real Rays (Rajidae) occur, the nail skate ( Raja clavata ), the starry ray ( Raja radiata ), the common skate ( Dipturus batis ) and the Cuckoo ray ( Raja naevus ). Other European species are the common stingray ( Dasyatis pastinaca ), the marble electric ray ( Torpedo marmorata ) and the Atlantic electric ray ( Torpedo nobiliana ).

features

Sequence of movements when undulating the pectoral fins in a real ray

Rays have a very flattened body and large pectoral fins that are fused with the head. The shoulder girdle is ring-shaped and connected to the spine in a fixed or articulated manner. Some of the anterior vertebrae are fused into a synarcual. The mouth, the nostrils and five pairs of gill slits are located on the flattened, mostly light-colored underside. On the top there are eyes and the vented spray holes through which the water for breathing enters. The upper eyelid is firmly attached to the eyeball. The top is adapted to the respective habitat of the ray, so it can range from sand-colored speckled to black. The upper jaw , the palatoquadratum, is not connected to the neurocranium , but is only supported by the large hyomandibular .

nutrition

Most rays feed on hard-shelled invertebrates such as clams , crabs, and echinoderms .

Locomotion

The fiddle rays as well as the saw rays and the electric ray-like move, like most plate gills (Elasmobranchi), by snaking the trunk of the body and the caudal fin. Real rays move their large pectoral fins in waves (undulation) and eagle rays flap them up and down like wings ("underwater flies").

Reproduction

All rays, with the exception of the common rays, which lay capsule-like eggs, are ovoviviparous . H. the young hatch in the mother's body or shortly after they have laid their eggs.

Systematics

External system

Amblyraja badia

The rays have traditionally been viewed as a cartilaginous fish taxon of the same rank as the sharks . In 1996 the Neoselachii (a taxon that includes the modern sharks and rays) were divided independently by de Carvalho and Shirai into two monophyletic taxa according to morphological characteristics , the Galeomorphii (Galea near Shirai), among which mainly large ones, which inhabit the open water Sharks are assigned, and the squalea , to which many bottom-dwelling as well as deep-sea sharks and also the rays belong. The shark's taxon would therefore be a paraphyletic (a form taxon ), the rays a subgroup of the squalomorphic sharks.

In the meantime, however, there are several molecular biological studies that 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.

Internal system

The internal systematics of the rays is highly controversial and there are several proposals. Wikipedia follows Aschliman and colleagues here, who take a phylogenetically oriented approach and divide the rays into two lines, the Rajiformes , which move through an undulating undulation of their pectoral fins and are called 'skates' in English, and a clade of all the other rays, in the English called 'rays', which, like most sharks, move by winding their trunk and tail fin or, as it were, fly through the water with even flaps of their wing-like pectoral fins (stingray-like).

The Rajiformes - most of the ray species occurring in the European marginal seas belong to this order - are now divided into four families, all of which used to belong to the family of real rays (Rajidae). The second large skate class combines the electric rays, the fiddle rays, the saw rays and the stingray, whereby the electric rays, together with their sister group , the thorn-back guitar rays (Platyrhinidae), occupy a basal position within this clade, followed by a clade of three genus of fiddle rays. The remaining rays are divided into a clade of fiddle rays and saw rays, for which Gavin JP Naylor and colleagues proposed the new order name Rhinopristiformes, and into the stingray-like (Myliobatoidei) with their sister group, the monotypical Zanobatoidei . The sawmills stand deep within a large fiddle- ray clade , with the fiddle- ray genus Glaucostegus as a sister group.

Internal systematics of the rays according to Ashhliman a. a. (2012) Internal systematics of the Myliobatoidei according to Aschliman a. a. (2012)
  Rays  
 "Skates" Rajiformes  


 Soft-nosed rays (Arhynchobatidae)


   

 Anacanthobatidae



   

 Real rays (Rajidae)



  "Rays"  

 Electric rays (Torpediniformes), including thornback guitar rays (Platyrhinidae)


   

 Trygonorrhinidae


   
  Rhinopristiformes  

 Rhinobatidae


   


 Sawfish (Pristidae)


   

 Glaucostegidae



   

 Rhinidae




  Myliobatiformes  
  Zanobatoidei 

 Zanobatidae


   

 Myliobatoidei 







Template: Klade / Maintenance / Style
  Myliobatoidei  

 Six-gill stingray (Hexatrygonidae)


   

 Deep water stingrays (Plesiobatidae)


   


 Butterfly rays (Gymnuridae)


   

 Round stingrays (Urolophidae)



   


 Stingrays (Dasyatidae)


   

 American round stingray (Urotrygonidae)


   

 Freshwater stingrays (Potamotrygonidae)




   

 Aetobatidae


   

 Myliobatidae


   

 Cow nose rays (Rhinopterinae)


   

 Devil rays (Mobulinae)









Template: Klade / Maintenance / Style

This concept of the relationship within the rays reflects the following systematics:

Tribal history

Asterodermus platypterus

Rays from the originally considered group of fiddle rays appear in fossil records in the Upper Jurassic . The genera Aellopos and Asterodermus are known from the Solnhofen limestone . Another fiddle ray is Rhombopterygia from the Upper Cretaceous Lebanon. The recent genus of fiddling rays Rhinobatos , Trygonorrhina and Zapteryx have been fossilized since the Lower Cretaceous and the Eocene .

literature

  • Joseph S. Nelson : Fishes of the World . 4th edition. John Wiley & Sons, 2006, ISBN 0-471-25031-7 .
  • Wilfried Westheide , Reinhard Rieger : Special Zoology Part 2: Vertebrae and Skull Animals . 1st edition. Spectrum Academic Publishing House, Heidelberg / Berlin 2004, ISBN 3-8274-0307-3 .
  • Bent J. Muus, Jørgen G. Nielsen; Preben Dahlström and Bente Olesen Nyström (illustrations): The marine fish of Europe. In the North Sea, the Baltic Sea and the Atlantic . (Original title: Havfisk og fiskeri i Nordvesteuropa 1998, translated by Matthias Stehmann), Franckh-Kosmos, Stuttgart 1999, ISBN 3-440-07804-3 .

Web links

Californian electric ray ( Torpedo californica )
Pristis pristis
Commons : Rays  - Collection of images, videos and audio files
Wiktionary: Rochen  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ a b c d Neil C. Aschliman, Mutsumi Nishida, Masaki Miya, Jun G. Inoue, Kerri M. Rosana, Gavin JP Naylord: Body plan convergence in the evolution of skates and rays (Chondrichthyes: Batoidea). In: Molecular Phylogenetics and Evolution. Volume 63, No. 1, April 2012, pp. 28-42. doi: 10.1016 / j.ympev.2011.12.012 .
  2. ↑ Bent J. Muus, Jørgen G. Nielsen; Preben Dahlström and Bente Olesen Nyström (illustrations): The marine fish of Europe. In the North Sea, the Baltic Sea and the Atlantic . (Original title: Havfisk og fiskeri i Nordvesteuropa 1998, translated by Matthias Stehmann), Franckh-Kosmos, Stuttgart 1999, ISBN 3-440-07804-3 .
  3. ↑ Spektrum.de . Batidoidimorpha . In: Compact Lexicon of Biology . Spectrum Academic Publishing House, Heidelberg. 2001
  4. ^ Alfred Goldschmid: Chondrichthyes. In: W. Westheide, R. Rieger: Special Zoology. Part 2. Vertebrate or skull animals. Spektrum, Munich 2004, ISBN 3-8274-0307-3 .
  5. ^ A b Joseph S. Nelson : Fishes of the World . John Wiley & Sons, 2006, ISBN 0-471-25031-7 .
  6. ↑ 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. In: Molecular Phylogenetics and Evolution , Vol. 26, No. 2, February 2003, pp. 215-221 doi: 10.1016 / S1055-7903 (02) 00333-0
  7. ↑ CJ Winchell, AP Martin, J. Mallatt: Phylogeny of elasmobranchs based on LSU and SSU ribosomal RNA genes. In: Molecular Phylogenetics and Evolution , 31 vol., No. 1, April 2004, pp. 214-224, doi: 10.1016 / j.ympev.2003.07.010 .
  8. ^ CJ Underwood: Diversification of the Neoselachii (Chondrichthyes) during the Jurassic and Cretaceous. In: Paleobiology , Volume 32, No. 2, 2006, pp. 215-235 (PDF).
  9. ↑ Gavin JP Naylor, Janine N. Caira, Kirsten Jensen, Kerri AM Rosana, Nicolas Straube, Clemens Lakner: Elasmobranch Phylogeny: A Mitochondrial Estimate Based on 595 Species. Page 43 in Jeffrey C. Carrier, John A. Musick, Michael R. Heithaus: Biology of Sharks and Their Relatives (Marine Biology). Publisher: Crc Pr Inc, 2012, ISBN 1-4398-3924-7 .
  10. ↑ a b White, WT & Naylor, GJP (2016): Resurrection of the family Aetobatidae (Myliobatiformes) for the pelagic eagle rays, genus Aetobatus. Zootaxa , 4139 (3): 435-438. doi: 10.11646 / zootaxa.4139.3.10
  11. ^ Last, PR, Weigmann, S. & Yang, L. (2016): Changes to the nomenclature of the skates (Chondrichthyes: Rajiformes). Pages 11 to 34 in Last, PR & Yearsley, GK (Ed.) (2016): Rays of the World: Supplementary information. CSIRO Australian National Fish Collection.
  12. ^ Last, PR, Séret, B. & Naylor, GJP (2016): A new species of guitarfish, Rhinobatos borneensis sp. nov. with a redefinition of the family-level classification in the order Rhinopristiformes (Chondrichthyes: Batoidea). Zootaxa , Vol 4117, No 4: 451-475. doi: 10.11646 / zootaxa.4117.4.1
  13. ^ Karl Albert Frickhinger: Fossil Atlas of Fish , Mergus-Verlag, Melle 1999, ISBN 3-88244-018-X .