Saltasaurus (which means “lizard from Salta”) is a genus of titanosaurid sauropod dinosaur of the Late Cretaceous 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 of bony plates embedded in its skin. Such small bony plates, called osteoderms, have since been found on other titanosaurids.
The fossils of Saltasaurus were excavated by José Fernando 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.
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 means “protected by small armoured plates” in Latin.
The holotype, 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 ilia. Under the inventory number PVL 4017 over two hundred additional fossils have been catalogued. These include rear skull elements, teeth, vertebrae of the neck, back, hip and tail, parts of the shoulder girdle and the pelvis, and limb bones — plus various pieces of armour. These bones represent a minimum of five individuals, two adults and three juveniles or subadults.
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 ankylosaurian. It has been suggested these plates were in fact from Saltasaurus.
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 8.5 metres, the weight at 2.5 tonnes. However, Donald Henderson in 2013 estimated the animal at 12.8 metres (42 ft) in length and 6.87 tonnes (7.57 short tons) in weight.
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 centra. Saltasaurus had vertebral lateral fossae, pleurocoels, that resembled shallow depressions. Fossae that similarly resemble shallow depressions are known from Malawisaurus, Alamosaurus, Aeolosaurus, and Gondwanatitan. 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. 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. 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.