Guitarfish Explained

The guitarfish, also referred to as shovelnose rays, are a family, Rhinobatidae, of rays. The guitarfish are known for an elongated body with a flattened head and trunk and small, ray-like wings. The combined range of the various species is tropical, subtropical, and warm temperate waters worldwide.

Names

In Australia and New Zealand, guitarfish are commonly referred to as shovelnose rays or shovelnose sharks.[1] [2]

Description

Guitarfish have a body form intermediate between those of sharks and rays. The tail has a typical shark-like form, but in many species, the head has a triangular, or guitar-like shape, rather than the disc-shape formed by fusion with the pectoral fins found in other rays.[3]

Reproduction

Guitarfish can be ovoviviparous; the embryo matures inside an egg within the mother until it is ready to hatch.[4] This is typical of rays.

Habitat

Guitarfish are bottom feeders that bury themselves in mud or sand and eat worms, crabs, and clams.[5] Some can tolerate salt, fresh, and brackish water.[6] They generally live close to the beach/coastline or in estuaries.[6]

Evolution

Rays, including guitarfish, belong to the ancient lineage of cartilaginous fishes. Fossil denticles (tooth-like scales in the skin) resembling that of today's chondrichthyans date at least as far back as the Ordovician, with the oldest unambiguous fossils of cartilaginous fish dating from the middle Devonian. A clade within this diverse family, the Neoselachii, emerged by the Triassic, with the best-understood neoselachian fossils dating from the Jurassic. This clade is represented today by sharks, sawfish, rays and skates.[7]

Classification

There are a number of issues in the taxonomy of Rhinobatidae, and many fish that were once in this family have been moved to their own families. Nelson's 2006 Fishes of the World recognized four genera in this family: Aptychotrema, Rhinobatos, Trygonorrhina, and Zapteryx. Of these, Aptychotrema, Trygonorrhina, and Zapteryx have been reclassified in the family Trygonorrhinidae. Several other taxa once placed in the Rhinobatidae, such as Platyrhinoidis and Rhina, have also been moved to their own families. Recently, the genus Glaucostegus has again become recognized as distinct from Rhinobatos, and now comprises its own family, Glaucostegidae.

Rhinobatos has been split in three genera based on genetic and morphological considerations: Rhinobatos, Acroteriobatus and Pseudobatos. Tarsistes is dubious and may be a synonym of Pseudobatos, and other genera formerly included in Rhinobatidae have been moved to Glaucostegidae, Rhinidae and Trygonorrhinidae.[8] [9] [10]

A 2021 re-evaluation of almost complete and articulated material from the Konservat-Lagerstätten of Bolca in Italy suggested that †"Rhinobatos" dezignii and †"Rhinobatos" primaevus should be excluded from Rhinobatos and assigned to the new genera †Pseudorhinobatos and †Eorhinobatos, respectively.[11]

Notes and References

  1. Web site: Eastern Shovelnose Ray, Aptychotrema rostrata (Shaw & Nodder, 1794) .
  2. Web site: Western Shovelnose Ray (Aptychotrema vincentiana) .
  3. Book: Paxton, J.R. . Eschmeyer, W.N.. Stevens, J. . Last, P.R.. 1998. Encyclopedia of Fishes. Academic Press. San Diego. 66. 0-12-547665-5.
  4. Web site: Blackchin Guitarfish . 2024-06-11 . Aquarium La Rochelle.
  5. Web site: Shovelnose guitarfish, Sandy Seafloor, Fishes, Rhinobatos productus at the Monterey Bay Aquarium. Monterey Bay Aquarium. Monterey Bay Aquarium Foundation. 1 May 2015.
  6. Web site: Sullivan. Taylor. FLMNH Ichthyology Department: Atlantic Guitarfish. Florida Museum of Natural History. 1 May 2015.
  7. http://www.ucmp.berkeley.edu/vertebrates/basalfish/chondrofr.html UCMP Berkeley "Chondrichthyes: Fossil Record"
  8. Book: Peter Last. William White. Marcelo de Carvalho. Bernard Séret. Matthias Stehmann. Gavin Naylor . Rays of the World . 2016 . . 9780643109148 .
  9. Book: Naylor, G.J.P.. Caira, J.N.. Jensen, K.. Rosana, K.A.M.. Straube, N.. Lakner, C. . 2012 . Elasmobranch Phylogeny: A Mitochondrial Estimate Based on 595 Species . Carrier, J.C.. Musick, J.A.. Heithaus, M.R. . Biology of Sharks and Their Relatives . 2nd . CRC Press, Boca Raton, Florida . 31–56. 9781439839249.
  10. Last, P.R.. Séret, B.. Naylor, G.J.P. . 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 . 4117 . 4 . 451–475 . 10.11646/zootaxa.4117.4.1 . 27395187.
  11. Giuseppe Marramà. Giorgio Carnevale. Gavin J. P. Naylor. Massimo Varese. Luca Giusberti. Jürgen Kriwet. Anatomy, taxonomy and phylogeny of the Eocene guitarfishes from the Bolca Lagerstätten, Italy, provide new insights into the relationships of the Rhinopristiformes (Elasmobranchii: Batomorphii). Zoological Journal of the Linnean Society . 192 . 4 . 2021 . 1090–1110 . 10.1093/zoolinnean/zlaa125. free.
  12. Cybium . 30 . 3 . 2006 . 262ff . Rhinobatos jimbaranensis and R. penggali, two new shovelnose rays (Batoidea: Rhinobatidae) from eastern Indonesia. . Last, White . Fahmi 2006 . amp.
  13. Ichthyological Research . 10.1007/s10228-004-0211-0 . 51 . 2 . 2004 . 153–158 . Rhinobatos nudidorsalis, a new species of shovelnose ray (Batoidea: Rhinobatidae) from the Mascarene Ridge, central Indian Ocean . Peter R. Last . Leonard J.V. Compagno . Kazuhiro Nakaya . 32090559 .

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