Argentinosaurus
Argentinosaurus (meaning “Argentine lizard”[1]) is a genus of titanosaur sauropod dinosaur first discovered by Guillermo Heredia in Argentina. The generic name refers to the country in which it was discovered.
The dinosaur lived on the then-island continent of South America somewhere between 97 and 93.5 million years ago,[2] during the Late Cretaceous Period. It is among the largest known dinosaurs.
Description
Not much of Argentinosaurus has been recovered. The holotype included only a series of vertebrae (six from the back, five partial vertebrae from the hip region), ribs of the right side of the hip region, a part of a rib from the flank, and the right fibula (lower leg bone). One of these vertebrae was 1.59 meters tall, and the fibula was about 1.55 meters (61 inches).[3]
In addition to these bones, an incomplete femur (upper leg bone, specimen number MLP-DP 46-VIII-21-3) is assigned to Argentinosaurus; this incomplete femur shaft has a minimum circumference of about 1.18 meters.[4] The proportions of these bones and comparisons with other sauropod relatives allow paleontologists to estimate the size of the animal.
Size
An early reconstruction by Gregory S. Paul estimated Argentinosaurus at between 30–35 metres (98–115 ft) in length and with a weight of up to 80–100 tonnes (88–110 short tons).[5][6]
The length of the skeletal restoration mounted in Museo Carmen Funes is 39.7 metres (130 ft) long and 7.3 metres (24 ft) tall at the shoulder.
This is the longest reconstruction in a museum and contains the original material, including a mostly complete fibula.[7] Other estimates have compared the fragmentary material to relatively complete titanosaurs to help estimate the size of Argentinosaurus.
In 2006 Carpenter used the more complete Saltasaurus as a guide and estimated Argentinosaurus at 30 metres (98 ft) in length.[8] An unpublished estimate used published reconstructions of Saltasaurus, Opisthocoelicaudia, and Rapetosaurus as guides and gave shorter length estimates of between 22–26 metres (72–85 ft).[9]
Weight estimates are less common, but Mazzetta et al. (2004) provide a range of 60–88 tonnes (66–97 short tons), and consider 73 tonnes (80 short tons) to be the most likely, making it the heaviest sauropod known from good material.[4]
More recently, it was estimated at 83.2 tonnes (91.7 short tons) by calculating the volume of the aforementioned Museo Carmen Funes skeleton.[7] Scott Hartman suggests that since Argentinosaurus is a basal titanosaur, it would have a shorter tail and narrower chest than Puertasaurus, suggesting that it was slightly smaller than other giant titanosaurs such as Puertasaurus and Alamosaurus.[10]
Discovery
The first fossils identified as Argentinosaurus were found in 1987 by a rancher in Argentina, who mistook the leg for a giant piece of petrified wood. A gigantic vertebra, approximately the size of a man, was also found.[1]
The type and only species, A. huinculensis, was described and published in 1993 by the Argentine palaeontologists José F. Bonaparte and Rodolfo Coria. Its more specific time-frame within the Cretaceous is the late Cenomanian faunal stage, ~96 to 94 million years ago.
The fossil discovery site is in the Huincul Formation of the Río Limay Subgroup in Neuquén Province, Argentina (the Huincul Formation was a member of the Río Limay Formation according to the naming of the time).[3]
https://en.wikipedia.org/wiki/Argentinosaurus
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"The length of the skeletal restoration mounted in Museo Carmen Funes is 39.7 metres (130 feet) long and 7.3 metres (24 feet) tall at the shoulder."
Size comparison, showing the isolated bones of the holotype specimen in white.
Each grid square = 1m [~3 feet]