Albertonectes
| Albertonectes | ||||||||||||
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Albertonectes , artistic representation of life |
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| Temporal occurrence | ||||||||||||
| Upper Chalk (Upper Campanium ) | ||||||||||||
| 76.4 to 72 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Albertonectes | ||||||||||||
| Kubo , Mitchell & Henderson , 2012 |
Albertonectes is a genus of plesiosaurs that lived in the Upper Cretaceous . The genus includes with albertonectes vanderveldei a single known type , which in 2012 based on a nearly perfectly preserved fossil missing skeleton only the skull, first described was. Albertonectes had the highest number of cervical vertebrae of all known vertebrates and the longest neck of all plesiosaurs in relation to the body.
The fossil was deposited in the Bearpaw Formation , dated from the late Campanian to Lower Maastrichtian and made up of deposits from the Western Interior Seaway , and was found while mining ammolite near Lethbridge in southern Alberta . Tooth prints on the raven beak, two scales from a shark of the genus Squalicorax and small disturbances in the context of the skeleton show that sharks ate the carcass. The species epithet vanderveldei was given in honor of Rene Vandervelde, who founded the ammolite mining company, without whose work the fossil would never have been found.
features
The almost completely preserved postcranial skeleton comprises 132 vertebrae from atlas and axis to the last fused caudal vertebrae, the shoulder girdle , an incomplete pelvis , almost complete fore and hind limbs, disarticulated ribs (outside the original anatomical structure), an abdominal rib and 97 gastroliths . The animal was 11.2 meters long, of which the neck, supported by 76 cervical vertebrae, accounted for seven meters (62%). In addition to the high number of cervical vertebrae, there is a distinction between lateral longitudinal ridges on the cervical vertebrae towards the body, a relatively wide clavicle , a tapering ventral protrusion on the middle symphysis of the raven's bill bone (original bone in the shoulder girdle), an anterolateral (front and side) protrusion of the pubic bone , the fused last caudal vertebrae and a relatively slender humerus albertonectes from other plesiosaurs. The gastroliths have a diameter of one to 13.5 cm. An analysis of their shape showed that most of them were taken near a beach.
Systematics
A preliminary phylogenetic analysis placed Albertonectes in a clade of long-necked elasmosaurids from the late Cretaceous period . Its closest relatives include Aristonectes , Styxosaurus , Terminonatator and Thalassomedon , but not Elasmosaurus , which has the second highest number of cervical vertebrae (72).
literature
- Tai Kubo, Mark T. Mitchell, Donald M. Henderson: Albertonectes vanderveldei, a new elasmosaur (Reptilia, Sauropterygia) from the Upper Cretaceous of Alberta. In: Journal of Vertebrate Paleontology. Vol. 32, No. 3, 2012, ISSN 0272-4634 , pp. 557-572, doi : 10.1080 / 02724634.2012.658124