Nurse sharks
| Nurse sharks | ||||||||||||
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Zebra shark ( Stegostoma fasciatum ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Orectolobiformes | ||||||||||||
| Applegate , 1972 |
The nurse shark-like (Orectolobiformes) are also called carpet-shark -like and are an order of the sharks (Selachii). The nurse shark species include the whale shark ( Rhincodon typus ), the largest shark and the largest fish today.
features
All nurse sharks have two stingless dorsal fins, an anal fin, an injection hole and five, relatively small gill slits, the last two to four of which are behind the attachment of the pectoral fin. The eyes are high on the head in many species. The mouth is relatively small and is usually clearly in front of the eyes. The nostrils are often provided with barbels and are connected to nasal pits.
Systematics
The nurse shark-like includes 45 species in 13 genera, seven families and two sub-orders.
- Order nurse shark (Orectolobiformes)
- Subordination Parascyllioidei , spray hole small, without gill filaments, fifth gill slit large, beginning of the anal fin in front of the second dorsal fin.
- Family collar carpet sharks (Parascyllidae) (8 species)
- Suborder Orectoloboidei , injection hole medium to large, with gill filaments, fifth gill slit medium-sized, beginning of the anal fin behind the second dorsal fin.
- Superfamily Orectoloboidea
- Blind sharks family (Brachaeluridae) (2 species)
- Carpet shark family (Orectolobidae) (12 species)
- Superfamily Hemiscylliioidea
- Family bamboo sharks (Hemiscylliidae) (17 species)
- Family zebra sharks (Stegostomatidae) ( monotypic )
- Family nurse sharks (Ginglymostomatidae) (4 species)
- Family whale sharks (Rhincodontidae) (monotypical)
- Superfamily Orectoloboidea
- Subordination Parascyllioidei , spray hole small, without gill filaments, fifth gill slit large, beginning of the anal fin in front of the second dorsal fin.
The probable family relationships are shown in the following cladogram , from which it follows that the nurse sharks are a paraphyletic taxon in relation to the zebra shark and the whale shark:
| Orectolobiformes |
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literature
- Joseph S. Nelson , Terry C. Grande, Mark VH Wilson: Fishes of the World. John Wiley & Sons, 2016, ISBN 978-1118342336 .
Individual evidence
- ↑ 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 41 in Jeffrey C. Carrier, John A. Musick, Michael R. Heithaus: Biology of Sharks and Their Relatives (Marine Biology). Publisher: Crc Pr Inc, 2012, ISBN 1-43983-924-7 .
Web links
- Nurse sharks on Fishbase.org (English)