Paluxysaurus

Paluxysaurus
Temporal occurrence
	Lower Cretaceous (late Aptian )
	123 to 112.9 million years
Locations
	USA , Texas ( Twin Mountains Formation );
Systematics
	Lizard dinosaur (Saurischia)
	Sauropods (Sauropoda)
	Neosauropoda
	Macronaria
	Brachiosauridae
	Paluxysaurus
Scientific name
	Paluxysaurus
	Rose , 2007
Art
	Paluxysaurus jonesi;

Paluxysaurus is a genus of sauropod dinosaur from the group of Brachiosauridae from the Lower Cretaceous North America. Fossil remains of this genus were discovered in the Twin Mountains Formation in Texas ( USA ) and can be dated to the late Aptian (about 123 to 113 million years ago). The only species is Paluxysaurus jonesi .

description

The skull is passed down through an upper jaw bone (maxilla) and a nasal bone (nasal). The upper jawbone is shorter than that of Brachiosaurus and more robust than that of Camarasaurus . One complete tooth and at least four tooth fragments have been preserved in the upper jawbone, and two other tooth fragments were discovered near the skull bones. There were probably 9 to 10 teeth on each side of the upper jaw. Important diagnostic features include the wide nasal process of the maxillary bone and a strong lateral curvature of the premaxillary process of the nasal bone. Unique features can also be found in the vertebral arches of the caudal and dorsal vertebrae.

Systematics

The cladistic analysis by Peter Rose (2007) sees Paluxysaurus within the Brachiosauridae as a sister taxon of Brachiosaurus , but also establishes a closer relationship with the North American sauropods Venenosaurus and Cedarosaurus . You and Li (2009) as well as Ksepka and Norell (2010) also come to the conclusion that Paluxysaurus can be classified as a Brachiosauridae. The latter authors classify Paluxysaurus in a clade together with Brachiosaurus , Giraffatitan , Cedarosaurus and Abydosaurus .

History of discovery, find and naming

All fossils come from a site within Jones Ranch in Hood County , Texas. In the vicinity of the site there are numerous fossil footprints of sauropods and theropods, the so-called Paluxy River footprints . The site was discovered by a group of students in the mid-1980s - subsequent excavations by Jeffrey G. Pittman began in 1985, but were stopped in 1987. Since 1993, a group of researchers from Southern Methodist University has continued paleontological fieldwork at the site. The rocks of the site were deposited fluviatil (by a river) and belong to the Twin Mountains Formation . The site shows an area of about 400 square meters; however, the sauropod fossils were found in association with each other, with individual bones mostly not being found more than a meter away from other bones.

The holotype (copy number FWMSH 93B-10-18) is a left upper jawbone with nasal bone and teeth. Other bones come from at least four different individuals and include isolated teeth, a series of 7 cervical vertebrae and two isolated cervical vertebrae, 13 dorsal vertebrae, more than 30 caudal vertebrae, rib fragments and chevron bones , shoulder blades (scapula), raven bones (coracoid), a sternum ( sternum), humerus (humerus), Elle (ulna) and spoke (radius), metacarpal bone (metacarpal), ilium (Ilia), pubic bones (pubes), ischium (Ischia), thigh bone (femora) shins (tibiae), fibula ( Fibulae) as well as three metatarsals. More bones were found but have yet to be prepared.

The genus was first scientifically described in 2007 by Peter J. Rose . The name Paluxysaurus refers to the town of Paluxy and the Paluxy River near the site . The second part of the species name honors William R. Jones, the owner of the ranch, who has approved excavation work on his land for two decades.

Individual evidence

^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 203, online .
↑ ^a ^b ^c ^d ^e ^f Peter J. Rose: A new titanosauriform sauropod (Dinosauria: Saurischia) from the Early Cretaceous of central Texas and its phylogenetic relationships. In: Palaeontologia Electronica. Vol. 10, No. 2, 2007, ISSN 1094-8074 , Article Number: 10.2.8A, online .
^ Hai-Lu You, Da-Qing Li: The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 276, No. 1675, 2009, ISSN 0080-4649 , pp. 4077-4082 doi : 10.1098 / rspb.2009.1278 .
^ Daniel T. Ksepka, Mark A. Norell : The Illusory Evidence for Asian Brachiosauridae: New Material of Erketu ellisoni and a Phylogenetic Reappraisal of Basal Titanosauriformes (= American Museum Novitates. No. 3700). American Museum of Natural History, New York NY 2010, (PDF; 448.89 kB) .

[paul_10-1] Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 203, online .

[rose_07-2] ↑ ^a ^b ^c ^d ^e ^f Peter J. Rose: A new titanosauriform sauropod (Dinosauria: Saurischia) from the Early Cretaceous of central Texas and its phylogenetic relationships. In: Palaeontologia Electronica. Vol. 10, No. 2, 2007, ISSN 1094-8074 , Article Number: 10.2.8A, online .

[you_09-3] Hai-Lu You, Da-Qing Li: The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia. In: Proceedings of the Royal Society. Series B: Biological Sciences. Vol. 276, No. 1675, 2009, ISSN 0080-4649 , pp. 4077-4082 doi : 10.1098 / rspb.2009.1278 .

[ksepka_10-4] Daniel T. Ksepka, Mark A. Norell : The Illusory Evidence for Asian Brachiosauridae: New Material of Erketu ellisoni and a Phylogenetic Reappraisal of Basal Titanosauriformes (= American Museum Novitates. No. 3700). American Museum of Natural History, New York NY 2010, (PDF; 448.89 kB) .