Sclerorhynchidae
Sclerorhynchidae | ||||||||||||
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Head and front body of Libanopristis hiram in the Museo Civico di Storia Naturale di Milano in Milan . |
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Temporal occurrence | ||||||||||||
Barremium to Maastrichtium ( chalk ) | ||||||||||||
83.5 to 70.6 million years | ||||||||||||
Locations | ||||||||||||
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Systematics | ||||||||||||
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Scientific name of the order | ||||||||||||
Sclerorhynchiformes | ||||||||||||
Kriwet, 2004 | ||||||||||||
Scientific name of the family | ||||||||||||
Sclerorhynchidae | ||||||||||||
Cappetta , 1974 |
The Sclerorhynchidae , the Germans also Scheinsägerochen or Pseudosägerochen called, are an extinct Roche family from the Cretaceous period . Outwardly they looked similar to the recent saw rays (Pristidae), but remained much smaller with a maximum length of 100 cm. They are likely the result of a convergent evolution , not closely related to the sawfish, nor their ancestors. They were spread all over the world, the main focus of the spread and probably the place of their origin was the Tethys . They reached their greatest biodiversity at the end of the Cretaceous Period in Maastricht , at the end of which they disappeared along with the dinosaurs and many other groups in the course of a great mass extinction .
features
Like the sawfish, the Sclerorhynchidae had an elongated, slightly disc-shaped and more shark-like body, a long rostrum with teeth on the sides, and lived near the coast as inhabitants of the seabed. They reached lengths of 70 to 100 cm. The two dorsal fins were positioned further back than those of the saw rays and the fiddle rays . The saw-like rostrum arose in the Sclerorhynchidae by lengthening the basal section of the rostral cartilage, whereas in the sawfish, the anterior part of the rostral cartilage lengthened. Propterygium, Mesopterygium and Metapterygium, the three basal, the fin rays transmitted cartilage of the pectoral fins are formed substantially larger than the Sägerochen and Propterygium and Mesopterygium contributed most fin rays. In addition, the jaw teeth of the pseudo-saw rays are generally relatively highly specialized, whereas those of the saw rays, like those of the fiddle rays, are unspecialized. The transition from the head to the rostrum took place more gently in the Sclerorhynchidae and is not as distinct as in the sawfish. The rostrum tapered from the base to the tip, while that of the saw ray is about the same width over the entire length. Another difference concerns the internal anatomy of the rostrum. There is a cavity in the rostrum that is a continuation of the brain cavity. The Sclerorhynchidae have only one unpaired, centrally located channel, a feature that is also found in the saw sharks (Pristiophoridae), which are not rays. The saw- ray genus Pristis , on the other hand, has another pair of channels on the side of the central cavity, Anoxypristis even has two paired channels. This contains nerves and the rostral artery.
Genera
To date, 23 genera with 40 species have been described, some of them only on the basis of their jaw teeth, so it is unclear whether they are pseudo-saw rays, saw rays or fiddle rays.
- Ankistrorhynchus Casier 1964
- Archingeayia Vullo, Cappetta & Neraudeau 2007
- Baharipristis Werner 1989
- Biropristis Suarez & Cappetta 2004
- Borodinopristis Case 1987
- Celtipristis Kriwet 1999
- Ctenopristis Arambourg 1940
- Dalpiazia Checchia-Rispoli 1933
- Ganopristis Arambourg 1935
- Ischyrhiza Leidy 1856
- Kiestus Cappetta & Case 1999
- Libanopristis Cappetta 1980
- Marckgrafia Weiler 1935
- Micropristis Cappetta 1980
- Onchopristis Stromer 1917
- Onchosaurus Gervais 1852
- Plicatopristis Cappetta 1991
- Ptychotrygon Jaeckel 1894
- Ptychotrygonoides Landemaine 1991
- Pucapristis Schaeffer 1963
- Renpetia Werner 1989
- Schizorhiza hamlet 1930
- Sclerorhynchus Woodward 1917
literature
- H. Capetta. 1974. Sclerorhynchidae nov. fam. Pristidae et Pristiophoridae: un exemple de parallelisme chez Selaciens. Comptes rendus de Academie de Sciences Paris Series D 278: 225-228
- Barbara E. Wueringer, Lyle Squire Jr., Shaun P. Collin: The biology of extinct and extant sawfish (Batoidea: Sclerorhynchidae and Pristidae). Reviews in Fish Biology and Fisheries. 05/2009; 19: 445-464. DOI: 10.1007 / s11160-009-9112-7
Web links
- Paleodatabase: † Family Sclerorhynchidae Capetta 1974