Loggerhead dogfish

Loggerhead dogfish
Chocolate shark ( Dalatias licha )
Systematics
Subclass : Euselachii Subclass : Plate gill (Elasmobranchii) without rank: Sharks (selachii) Superordinate : Squalomorphii Order : Spiny dogfish (Squaliformes) Family : Loggerhead dogfish
Scientific name
Dalatiidae
Gray , 1851

The loggerhead dogfish (Dalatiidae) are a family of small sharks that live in the Atlantic , Pacific and Indian Oceans in the open water as well as on continental slopes and shelf areas of continents and islands.

features

The Dalatiidae are small sharks that are only 22 to 42 centimeters long. The only exception is the chocolate shark ( Dalatias licha ), which can reach a length of 1.80 meters. All Dalatiidae lack the anal fin . The species of the genus Squaliolus only have a spine in front of the first dorsal fin , in all other Dalatiidae the dorsal fins are thornless. There can be light organs on the underside of the front body .

Reproduction

All Dalatiidae are ovoviviparous , which means that the embryos hatch from their egg capsules in the womb and develop in the uterine region to the size of birth and are then born alive. One also speaks of "aplacental viviparia ".

Genera and species

Pygmy shark ( Euprotomicrus bispinatus )

Cigar shark ( Isistius brasiliensis )

Pygmy shark ( Squaliolus laticaudus )

There are seven genera and ten species .

• Genus: Dalatias (Rafinesque, 1810)
  • Chocolate shark ( Dalatias licha (Bonnaterre, 1788) )
• Genus: Euprotomicroides (Hulley & Penrith, 1966)
  • Tail light shark ( Euprotomicroides zantedeschia (Hulley & Penrith, 1966) )
• Genus: Euprotomicrus (Gill, 1865)
  • Pygmy shark ( Euprotomicrus bispinatus (Quoy & Gaimard, 1824) )
• Genus: Heteroscymnoides (Fowler, 1934)
  • Long-nosed pygmy shark ( Heteroscymnoides marleyi (Fowler, 1934) )
• Genre : Mollisquama (Dolganov, 1984)
  • Mollisquama mississippiensis Grace et al., 2019
  • Pocket shark ( Mollisquama parini (Dolganov, 1984) )
• Genus: Cigar sharks ( Isistius (Gill, 1865) )
  • Cigar shark ( Isistius brasiliensis (Quoy & Gaimard, 1824) )
  • Big-toothed cigar shark ( Isistius plutodus (Garrick & Springer, 1964) )
• Genus: Squaliolus (Smith & Radcliffe in Smith, 1912)
  • Small-eyed pygmy shark ( Squaliolus aliae (Teng, 1959) )
  • Pygmy shark ( Squaliolus laticaudus (Smith & Radcliffe in Smith, 1912) )

literature

• Joseph S. Nelson , Fishes of the World , John Wiley & Sons, 2006, ISBN 0-471-25031-7 .
• Kurt Fiedler, Textbook of Special Zoology, Volume II, Part 2: Fish , Gustav Fischer Verlag Jena, 1991, ISBN 3-334-00339-6 .

Web links

Commons : Dalatiidae  - collection of images, videos and audio files

• Loggerhead dogfish on Fishbase.org (English)