Patagosaurus
| Patagosaurus | ||||||||||
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Artistic live representation of Patagasaurus fariasi |
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| Temporal occurrence | ||||||||||
| Lower to Middle Jurassic (Upper Toarcian to Lower Bathonian ) | ||||||||||
| 178.2 to 167.4 million years | ||||||||||
| Locations | ||||||||||
| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Patagosaurus | ||||||||||
| Bonaparte , 1979 | ||||||||||
| Art | ||||||||||
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Patagosaurus ("Patagonian lizard") is a genus of sauropod dinosaur from the Lower to Central Jurassic of Argentina . As with all sauropods, it was a large, four-legged herbivore with a long neck and tail. This genus is known from the fragmentary remains of at least twelve individuals, making it currently the best known Jurassic sauropod in South America. The remains come from both adults and young animals, which allows conclusions to be drawn about the individual development of these animals. Furthermore, indications of a possible life in groups were described. Patagosaurus was an original representative of the sauropods and as such is traditionally placed among the Cetiosauridae , although the validity of this group is disputed. It was first scientifically described in 1979 by the paleontologist José Bonaparte with the only species Patagosaurus fariasi .
features
Patagosaurus reached a body length of up to 14 meters, the largest traditional thigh bones measure a length of 52 centimeters. This genus is larger than the contemporary genus Volkheimeria , which comes from the same rock layers known as the Cañadón-Asfalto Formation .
The skull is only passed down through teeth and jawbones ( premaxillary , upper jaw and dentals). It was short and deep and resembled that of the Camarasaurus . The tooth crowns of the upper jaw were spatulate and constricted at their lower end; serration was missing. The spine is incomplete. The cervical vertebrae were elongated and resembled those of Cetiosaurus , while the vertebrae were relatively short. While the vertebral bodies of the cervical vertebrae showed clear lateral cavities, these cavities in the vertebrae were less pronounced. The sacrum consisted of five sacral vertebrae fused together. The thigh bone was almost straight and showed a pronounced fourth trochanter , while the relatively short tibia had a very pronounced cnemial ridge .
Systematics
Patagosaurus is classified within the Eusauropoda , a group that includes all sauropods except for a few original representatives. The Eusauropoda, in turn, consisted of various original genera and the Neosauropoda , to which all later, more advanced sauropods belong. Patagosaurus is classified outside of the Neosauropoda in previous studies.
The exact systematic position of Patagosaurus within the Eusauropda is unknown. Traditionally it is classified within a group called Cetiosauridae , which many researchers today regard as paraphyletic and therefore invalid. Most recently, the Cetiosauridae was recognized by Paul Upchurch and colleagues (2004) as a monophyletic group to summarize the genera Barapasaurus , Cetiosaurus and Patagosaurus . Fernando Novas (2009), on the other hand, sees Patagosaurus as the sister taxon of the Neosauropoda.
Location
The fossils come from the Argentine province of Chubut near the village of Cerro Cóndor . The here open-minded rock layers belong to Cañadón Asfalto Formation . Although this formation was once dated to the Callovian (Upper Middle Jurassic), today it is assumed that it is significantly older and was deposited between the upper Toarcian and the lower Bathonian . Patagosaurus is the most commonly found dinosaur of the Cañadón Asfalto Formation. Other dinosaur finds include the early sauropod Volkheimeria , the theropod Eoabelisaurus , Piatnitzkysaurus and Condorraptor, and the heterodontosaurid Manidens .
Paleoecology and paleobiology
The well-known Patagosaurus fossils belong to both adults and young animals, which allows conclusions to be drawn about the individual development (ontogenesis) of these animals: For example, young animals showed low spinous processes of the vertebrae with small lateral cavities, while the spinous processes in adult animals were relatively higher and had cavities reaching to their tips.
Rodolfo Coria (1994) notes that the remains of five of the known specimens were found together in an area of 15 by 4 meters. This bonebed ("bone bed") consists exclusively of the remains of Patagosaurus , while the remains of other animals are missing (monospecific socialization). Coria interprets this finding as a possible indication of a life in groups: It could have been a group that died together as a result of a catastrophic event such as a storm surge. Coria also notes that the group consists of two adults and three young animals of different ages. According to this researcher, this could indicate a relatively complex social behavior of these animals, which could also include brood care.
Individual evidence
- ^ A b Diego Pol, Oliver WM Rauhut : A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 279, No. 1741, 2012, ISSN 0080-4649 , pp. 3170-3175, doi : 10.1098 / rspb.2012.0660 , Supplementary Information, Section: Cañadón Asfalto Formation.
- ^ A b Paul Upchurch , Paul M. Barrett , Peter Dodson : Sauropoda. In: David B. Weishampel , Peter Dodson, Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 259-324, here pp. 301-302.
- ↑ a b c d e f Fernando E. Novas : The age of dinosaurs in South America. Indiana University Press, Bloomington IN et al. 2009, ISBN 978-0-253-35289-7 , pp. 103-107.
- ^ José F. Bonaparte : Dinosaurs: a Jurassic assemblage from Patagonia. In: Science . Vol. 205, No. 4413, 1979, pp. 1377-1379, doi : 10.1126 / science.205.4413.1377 .
- ^ A b Donald F. Glut : Dinosaurs. The Encyclopedia. McFarland & Company, Jefferson NC et al. 1997, ISBN 0-89950-917-7 , pp. 686-688.
- ^ Rodolfo A. Coria : On a monospecific assemblage of Sauropod Dinosaurs from Patagonia: Implications for gregarious behavior. In: Gaia. Revista de Geociências. No. 10, 1994, ISSN 0871-5424 , pp. 209-213, digitized version (PDF; 1.18 MB) .
