Mendozasaurus

Mendozasaurus
Temporal occurrence
Upper Cretaceous ( Turonium to Coniacium )
93.9 to 86.3 million years
Locations
Argentina , Mendoza ( Neuquén Group )
Systematics
Dinosaur (dinosauria) Lizard dinosaur (Saurischia) Sauropodomorpha Sauropods (Sauropoda) Titanosaurs (Titanosauria) Mendozasaurus
Scientific name
Mendozasaurus
Gonzáles Riga , 2003
Art
Mendozasaurus neguyelap

Mendozasaurus is a genus of sauropod dinosaur from the Titanosauria group thatlived in South Americaduring the Upper Cretaceous .

So far, fragmentary remains are known that include the majority of the limbs and a series of caudal vertebrae and are dated to the late Turonian to late Coniacian . Like some other titanosaurs, it wore skin bone plates ( osteoderms ). The only known species is Mendozasaurus neguyelap .

features

Mendozasaurus was a large titanosaur and is estimated to be 18 to 27 meters in length. As with all sauropods, it is a four-legged herbivore with a long neck and tail. Together with the type skeleton, two small and two large osteoderms were found: The small osteoderms correspond to the shape of an ellipsoid (are convex on the upper and lower sides) and reach a length of 8.1 cm and a height of 4.4 cm; unlike Saltasaurus , they have no spines. The larger osteoderms reach 17.5 cm in length and 15.3 cm in height, but are only slightly convex on the underside. This type shows similarities with the osteoderms of Ampelosaurus . As with other titanosaurs, the osteoderms were probably not used for defense - instead, they were possibly calcium reserves.

It can be distinguished from related genera by a unique combination of features: For example, the posterior central cervical vertebrae have high spinous processes that are laterally fan-like and are significantly wider than the vertebral bodies. The middle caudal vertebrae are moderately procoel (concave on the front), with the posterior articular knots (condyles) being greatly reduced and shifted upwards.

Systematics

Within the Titanosauria, Mendozasaurus is part of the Titanosauridae (= Lithostrotia ). It is considered a close relative of Futalognkosaurus - both genera are also combined as Lognkosauria . Malawisaurus has been suggested as the sister taxon of the Longkosauria . The Traukutitan described in 2011 could be another, late representative of the Lognkosauria.

This cladogram has been simplified according to Calvo and colleagues (2007):

	Malawisaurus   Lognkosauria   Mendozasaurus     Futalognkosaurus

Research history, finds and naming

All finds so far come from a site south of Cerro Guillermo in the Argentine province of Mendoza . The first fossils were discovered by two oil workers. Between 1998 and 2001 palaeontological expeditions took place, which dug in the Mendozasaurus site and nearby sites and, in addition to the Mendozasaurus type specimen, found other fossils of titanosaurs, theropods and turtles. Between 2001 and 2003, Mendozasaurus cervical vertebrae were also recovered. The rocks of the site were deposited by rivers (fluviatil) in a flood plain. They are assigned to the Río Neuquén subgroup , a member of the Neuquen group . The Mendozasaurus fossils are now in the Instituto Argentino de Nivología des Glaciología y Ciencias Ambientales .

The holotype material (copy number IANIGLA-PV 065 / 1-24: 22) consists of 22 caudal vertebrae and two chevron bones , most of which are anatomically combined . Together with the holotype, various bones, torn from their anatomical context, were found, including a vertebra, a breastbone (sternum), a shoulder blade (scapula), parts of the arm (a humerus (humerus), ulna and radius (radius and ulna) and four metacarpal), parts of a pubic bone and parts of the rear legs (thigh bone (femur), tibia (tibia), fibula (Fibla), five metatarsal bones (metatarsals), two claws). While the holotype specimen comes from a relatively slender adult individual estimated to be 18 meters long, the other bones belong to at least one other individual who was about 15% larger. Larger fossils have been found nearby. Later cervical vertebrae from the same site were assigned to this genus.

Mendozasaurus was first scientifically described in 2003 by Bernardo González Riga . The name refers to the province of Mendoza. The second part of the species name, neguyelap , is made up of two indigenous words from the Millcayac language: neguy - "first" and yelap - "beast". This name is intended to indicate the fact that it is the first named dinosaur discovered in the province of Mendoza.

Individual evidence

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. 207, online .
2. ↑ Bernardo J. González Riga, Ricardo A. Astini: Fossil preservation of large titanosaur sauropods in overbank fluvial facies: a case study in the Cretaceous of Argentina. In: Journal of South American Earth Sciences. Vol. 23, No. 4, 2007, ISSN  0895-9811 , pp. 290–303, digitized version (PDF; 3.24 MB) ( Memento of the original from January 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. . 
3. ↑ Michael D. D'Emic, Jeffrey A. Wilson, Sankar Chatterjee : The titanosaur (Dinosauria: Sauropoda) osteoderm record: review and first definitive specimen from India. In: Journal of Vertebrate Paleontology. Vol. 29, No. 1, 2009, ISSN  0272-4634 , pp. 165-177, doi : 10.1671 / 039.029.0131 .
4. ↑ Thiago da Silva Marinho: Functional aspects of titanosaur osteoderms. In: Nature Precedings. 2007, ZDB -ID 2637018-9 , doi : 10.1038 / npre.2007.508.1 .
5. ↑ ^{a b} Jorge O. Calvo, Juan D. Porfiri, Bernardo J. Gonzáles-Riga, Alexander WA Kellner: A new Cretaceous terrestrial ecosystem from Gondwana with the description of a new sauropod dinosaur. In: Anais da Academia Brasileira de Ciências. Vol. 79, No. 3, 2007, ISSN  0001-3765 , pp. 529-541, digital version (PDF; 836.43 kB) .
6. ↑ Bernardo J. González Riga, Elena Previtera, Cecilia A. Pirrone: Malarguesaurus florenciae gen. Et sp. nov., a new titanosauriform (Dinosauria, Sauropoda) from the Upper Cretaceous of Mendoza, Argentina. In: Cretaceous Research. Vol. 30, No. 1, 2009, ISSN  0195-6671 , pp. 135-148, doi : 10.1016 / j.cretres.2008.06.006 .
7. ^ Ruben D. Juárez Valieri, Jorge O. Calvo: Revision of MUCPv 204, a Senonian basal titanosaur from northern Patagonia. In: Jorge Calvo, Juan Porfiri, Bernardo González Riga, Domenica Dos Santos (eds.): Paleontología y dinosaurios desde América Latina (= Series Documentos y Testimonios. Aportes. No. 24). EDIUNC, Mendoza 2011, ISBN 978-950-39-0265-3 , pp. 143–152, online (PDF; 612.13 MB) ( Memento of the original of July 6, 2011 in the Internet Archive ) Info: The archive link was automatically used and not yet tested. Please check the original and archive link according to the instructions and then remove this notice. . 
8. ↑ ^{a b} Bernardo J. González Riga: Nuevos restos fósiles de Mendozasaurus neguyelap (Sauropoda: Titanosauridae) del Cretácico Tardío de Mendoza, Argentina. In: Ameghiniana . Vol. 42, No. 3, 2005, pp. 535–538, digitized version (PDF; 545.92 kB) ( Memento of the original from September 3, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . 
9. ↑ ^{a b c} Bernardo J. González-Riga: A new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous of Mendoza Province, Argentina. In: Ameghiniana. Vol. 40, No. 2, 2003, pp. 155–172, digitized version (PDF; 3.99 MB) ( Memento of the original from September 3, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .