Editing Saltasaurus

{{Short description|Extinct genus of dinosaurs}}
{{speciesbox
| fossil_range = [[Late Cretaceous]], {{fossilrange|70|68}}
| image = Saltasaurus_dinosaur.png
| image_upright = 1.2
| image_caption = Life restoration
| genus = Saltasaurus 
| parent_authority= [[José Bonaparte|Bonaparte]] & [[Jaime Eduardo Powell|Powell]], 1980
| species = loricatus
| authority = Bonaparte & Powell, 1980
| synonyms =
*''[[Loricosaurus]] scutatus''? <br /><small>von Huene, 1929</small>
}}

'''''Saltasaurus''''' (which means "lizard from [[Salta]]") is a [[genus]] of [[saltasaurid]] [[dinosaur]] of the Late [[Cretaceous]] [[Period (geology)|period]] of [[Argentina]]. Small among sauropods, though still heavy by the standards of modern creatures, ''Saltasaurus'' was characterized by a short neck and stubby limbs. It was the first genus of sauropod known to possess [[Armour (zoology)|armour]] of bony plates embedded in its skin. Such small bony plates, called [[osteoderms]], have since been found on other [[titanosauria]]ns.

==Discovery==
[[File:Saltasaurus.jpg|left|thumb|A large osteoderm]]
The fossils of ''Saltasaurus'' were excavated by [[José Bonaparte]], Martín Vince and Juan C. Leal between 1975 and 1977 at the Estancia "El Brete". The find was in 1977 reported in the scientific literature.<ref>J.F. Bonaparte, J.A. Salfity, G. Bossi & J.E. Powell, 1977, "Hallazgo de dinosaurios y aves cretacicas en la Formación Lecho de El Brete (Salta), proximo al limite con Tucumán", ''Acta Geològica Lilloana'' '''14''': 5-17</ref>

''Saltasaurus'' was named and described by Bonaparte and Jaime E. Powell in 1980. The [[type species]] is ''Saltasaurus loricatus''. Its generic name is derived from [[Salta Province]], the region of north-west Argentina where the first fossils were recovered. The [[specific name (zoology)|specific name]] means "protected by small armoured plates" in [[Latin]].<ref>J.F. Bonaparte and J.E. Powell, 1980, "A continental assemblage of tetrapods from the Upper Cretaceous beds of El Brete, northwestern Argentina (Sauropoda-Coelurosauria-Carnosauria-Aves)," ''Mémoires de la Société Géologique de France, Nouvelle Série'' '''139''': 19-28</ref>

The [[holotype]], '''PVL 4017-92''', was found in a layer of the [[Lecho Formation]] dating from the early [[Maastrichtian]] stage of the [[Upper Cretaceous]] period, about seventy million years old. It consists of a [[sacrum]] connected to two [[ilium (bone)|ilia]]. Under the inventory number PVL 4017 over two hundred additional fossils have been catalogued. These include rear skull elements, teeth, [[vertebra]]e of the neck, back, hip and tail, parts of the shoulder girdle and the pelvis, and limb bones &mdash; plus various pieces of armour. These bones represent a minimum of five individuals, two adults and three juveniles or subadults.<ref name="Powell1992">Powell, J.E., 1992, "Osteología de ''Saltasaurus loricatus'' (Sauropoda Titanosauridae) del Cretácico Superior del noroeste Argentino" In: Sanz, J., Buscalioni, A. (Eds.), ''Los dinosaurios y su entorno biótico: Actas del Segundo Curso de Paleontología in Cuenca'', pp. 165-230</ref>

Currently the only recognised [[species]] of ''Saltasaurus'' is ''S. loricatus''. A ''S. robustus'' and a ''S. australis'' have been suggested but these are now considered to belong to a separate [[genus]], ''[[Neuquensaurus]]''. Earlier, armour plates from the area had been named as ''[[Loricosaurus]]'' by [[Friedrich von Huene]] who assumed them to be from an armoured [[ankylosaur]]ian. It has been suggested these plates were in fact from ''Saltasaurus''.

==Description==
[[File:Saltasaurus environment.jpg|thumb|left|''Saltasaurus'' herd passes [[abelisaurids]] and ''[[Noasaurus]]'']]
[[File:Saltasaurus size.png|thumb|300px|Size comparison of ''Saltasaurus'', size based on Donald Henderson]]
''Saltasaurus'' is very small compared to most other members of the Sauropoda. Powell estimated the adult length at six metres. In 2010, [[Gregory S. Paul]] estimated the maximum length at {{convert|8.5|m|ft|abbr=on}} and the weight at 2.5 tonnes (2.8 short tons).<ref>Paul, G.S., 2010, ''The Princeton Field Guide to Dinosaurs'', Princeton University Press p. 213</ref>  Donald Henderson estimated a larger size of {{convert|10.6 to 12.1|m|ft|abbr=on}} long.<ref>{{cite journal|last1=Henderson|first1=Donald|year=2013|title=Sauropod Necks: Are They Really for Heat Loss?|journal=PLOS ONE|volume=8|issue=10|pages=e77108|doi=10.1371/journal.pone.0077108|doi-access=free |pmid=24204747|pmc=3812985 |bibcode=2013PLoSO...877108H}}</ref>

The teeth of ''Saltasaurus'' were cylindrical, with spatulate points. ''Saltasaurus'' had a relatively short neck with shortened neck vertebrae. The vertebrae from the middle part of its tail had elongated [[Vertebral column|centra]].<ref name="veneno-caudal-145" /> ''Saltasaurus'' had vertebral lateral fossae, pleurocoels, that resembled shallow depressions.<ref name="veneno-caudal-147" /> Fossae that similarly resemble shallow depressions are known from ''[[Malawisaurus]]'', ''[[Alamosaurus]]'', ''[[Aeolosaurus]]'', and ''[[Gondwanatitan]]''.<ref name="veneno-caudal-147" /> ''Venenosaurus'' also had depression-like fossae, but its pleurocoels penetrated deeper into the vertebrae, were divided into two chambers, and extend farther into the vertebral columns.<ref name="veneno-caudal-147" /> In ''Saltasaurus'', the vertebral bone was generally [[cancellous]] and there were larger air chambers present as well. The limbs were short and stubby with especially short hands and feet. ''Saltasaurus'' had more robust radii than ''[[Venenosaurus]]''.<ref name="veneno-forelimb-148" /> The belly was extremely wide.

The osteoderms came in two types. There were larger oval plates with a length of up to twelve centimetres. These were keeled or spiked and perhaps were ordered in longitudinal rows along the back. The second type consists of small ossicles, rounded or pentagonal, about seven millimetres in diameter, that formed a continuous armour between the plates. A study in 2010 concluded that the larger plates had cancellous bone but that the ossicles had a denser bone tissue.<ref>Ignacio A. Cerda and Jaime E. Powell, 2010, "Dermal Armor Histology of ''Saltasaurus loricatus'', an Upper Cretaceous Sauropod Dinosaur from Northwest Argentina", ''Acta Palaeontologica Polonica'', '''55'''(3): 389-398</ref>

==Phylogeny==
''Saltasaurus''  in a [[cladogram]] after Navarro ''et al''., 2022:<ref name="Ibirania">{{Cite journal |last1=Navarro |first1=Bruno A. |last2=Ghilardi |first2=Aline M. |last3=Aureliano |first3=Tito |last4=Díaz |first4=Verónica Díez |last5=Bandeira |first5=Kamila L. N. |last6=Cattaruzzi |first6=André G. S. |last7=Iori |first7=Fabiano V. |last8=Martine |first8=Ariel M. |last9=Carvalho |first9=Alberto B. |last10=Anelli |first10=Luiz E. |last11=Fernandes |first11=Marcelo A. |last12=Zaher |first12=Hussam |date=2022-09-15 |title=A new nanoid titanosaur (Dinosauria: Sauropoda) from the Upper Cretaceous of Brazil |url=https://www.researchgate.net/publication/362978138 |journal=Ameghiniana |language=en |volume=59 |issue=5 |pages=317–354 |doi=10.5710/AMGH.25.08.2022.3477 |bibcode=2022Amegh..59..477N |s2cid=251875979 |issn=1851-8044}}</ref>

{{clade|style=font-size:90%; line-height:90%;
|label1=[[Saltasauridae]]
|1={{clade
 |label1=[[Opisthocoelicaudiinae]]
 |1={{clade
    |1=''[[Opisthocoelicaudia]]''
    |2=''[[Nemegtosaurus]]''}}
 |label2=[[Saltasaurinae]]
 |2={{clade
    |1={{clade
       |1=''[[Alamosaurus]]''
       |2=''[[Baurutitan]]''}}
    |2={{clade
       |1={{clade
          |1=''[[Ibirania]]''
          |2={{clade
             |1=''[[Bonatitan]]''
             |2=''[[Rocasaurus]]''}} }}
       |label2=[[Saltasaurini]]
       |2={{clade
          |1=''[[Neuquensaurus]]''
          |2={{clade
             |1=MACN-PV-RN 233
             |2='''''Saltasaurus'''''}} }} }} }} }} }}

==Palaeobiology==
[[File:Saltasaurus loricatus egg.JPG|thumb|Egg on display at the [[North American Museum of Ancient Life]]]]
Like all sauropods, ''Saltasaurus'' was [[herbivore|herbivorous]]. Because of its barrel-like rump, shaped like a [[hippopotamus]], Powell suggested that ''Saltasaurus'' was aquatic. Despite its small stature, ''Saltasaurus'' was still graviportal like other sauropods, meaning it could not run because its hindlimbs had to be held straight at the load-bearing phase of their walking cycle. Powell assumed adult individuals were protected against predators by their body armour, while juveniles were protected by the herd as a whole.<ref name="Powell1992"/>

In the [[Cretaceous]] Period, sauropods in [[North America]] were no longer the dominant group of herbivorous dinosaurs with the exception of ''[[Alamosaurus]]'', with the ornithopod and ceratopsian dinosaurs, such as ''[[Edmontosaurus]]'' and ''[[Triceratops]]'', becoming the most abundant (this being most evident by the Late Cretaceous epoch). However, on other landmasses such as [[South America]] and [[Africa]] (which were island [[continents]] much like modern [[Australia]]) sauropods, in particular the [[titanosaur]]s, continued to be the dominant herbivores.

''Saltasaurus'' was one such titanosaur sauropod, and lived around 70&nbsp;[[million years ago]]. When it was first discovered, in 1975, it forced [[palaeontologist]]s to reconsider some assumptions about sauropods as ''Saltasaurus'' possessed crocodile-like armour (osteoderms) 10 to 12&nbsp;centimetres (4 to 5&nbsp;in) in diameter. Previously, it had been assumed that size alone was sufficient defence for the massive sauropods. Since then, palaeontologists have investigated the possibility that other sauropods may also have had armour; for example,  ''[[Laplatasaurus]]''.

A new discovery, from another formation, may shed light on the nesting habits of ''Saltasaurus''. A large titanosaurid [[nest]]ing ground was discovered in Auca Mahuevo, in [[Patagonia]], [[Argentina]] (another titanosaur nesting site has reportedly been discovered in [[Spain]]). Several hundred female saltasaurines dug holes with their back feet, laid eggs in clutches averaging around 25 eggs each, and buried the nests under dirt and vegetation. The small [[egg (biology)|egg]]s, about 11&ndash;12&nbsp;cm (4&ndash;5&nbsp;in) in [[diameter]], contained [[fossil]]ised [[embryo]]s, complete with [[skin]] impressions showing a mosaic armour of small bead-like scales. The armour pattern resembled that of ''Saltasaurus''.<ref name="coria-chiappe-2007" />

==Footnotes==
{{Reflist|3|refs=
<ref name="veneno-caudal-145">"Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 145.</ref>
<ref name="veneno-caudal-147">"Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 147.</ref>
<ref name="veneno-forelimb-148">"Forelimb," Tidwell, Carpenter, and Meyer (2001). Page 148.</ref>
<ref name="coria-chiappe-2007">Coria and Chiappe (2007).</ref>

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==References==
* Coria, R.A. and Chiappe, L.M. 2007.[http://jpaleontol.geoscienceworld.org/cgi/content/abstract/81/6/1528 Embryonic Skin From Late Cretaceous Sauropods (Dinosauria) of Auca Mahuevo, Patagonia, Argentina.] Journal of Paleontology v81(6):1528-1532 {{doi|10.1666/05-150.1}}
* Tidwell, V., Carpenter, K. & Meyer, S. 2001. New Titanosauriform (Sauropoda) from the Poison Strip Member of the Cedar Mountain Formation (Lower Cretaceous), Utah. In: Mesozoic Vertebrate Life. D. H. Tanke & K. Carpenter (eds.). Indiana University Press, Eds. D.H. Tanke & K. Carpenter. Indiana University Press. 139–165.

==Further reading==
* ''Walking on Eggs: The Astonishing Discovery of Thousands of Dinosaur Eggs in the Badlands of Patagonia'', by Luis Chiappe and Lowell Dingus. June 19, 2001, Scribner. {{ISBN|0-7432-1211-8}}.

==External links==
{{wikispecies|Saltasaurus}}
{{commons category|Saltasaurus}}

*[https://web.archive.org/web/20080615211132/http://www.palaeos.com/Vertebrates/Units/330Sauropodomorpha/330.600.html#Saltasaurus Sauropodomorpha: Titanosauridae: 'Saltasaurus''], by [[M. Alan Kazlev]], from Palæos.
* [http://www.luisrey.ndtilda.co.uk/html/patagonia.htm The late Cretaceous nesting grounds of Patagonia] {{Webarchive|url=https://web.archive.org/web/20081028183335/http://www.luisrey.ndtilda.co.uk/html/patagonia.htm |date=2008-10-28 }}, by [[Luis Rey|Luis V. Rey]], from his art gallery.

{{Portal|Dinosaurs}}
{{Sauropodomorpha|T.}}
{{Taxonbar|from=Q131111}}

[[Category:Saltasauridae]]
[[Category:Dinosaur genera]]
[[Category:Maastrichtian dinosaurs]]
[[Category:Lecho Formation]]
[[Category:Taxa named by José Bonaparte]]
[[Category:Taxa named by Jaime Powell]]
[[Category:Fossil taxa described in 1980]]
[[Category:Dinosaurs of Argentina]]