Agustinia

*Agustinia ligabuei*

***Agustinia*** /ɑːɡəˈstɪniə/ is a genus of sauropod dinosaurs from the Early Cretaceous Period of South America. It contains the single species *Agustinia ligabuei*, a single specimen of which was recovered from the Lohan Cura Formation of Neuquen Province in Argentina, thought to date from the late Aptian to Albian stages of the Early Cretaceous Period, between 116 and 100 million years ago.

The name *Agustinia* honors the discoverer of the specimen, *Agustin Martinelli*. This dinosaur was originally named in a 1998 abstract written by famous Argentine paleontologist Jose Bonaparte. The original generic name was "Augustia", which, as it turned out, was already preoccupied by a beetle (see also: *Megapnosaurus*, *Protognathosaurus*). Bonaparte changed the name to *Agustinia* in a full paper published in 1999. There is one named species (*A. ligabuei*), which is named in honor of Dr. Giancarlo Ligabue, a philanthropist who provided financial support to the expedition which recovered the remains.

## Description

Only fragmentary remains are known. These include fragments of vertebrae from the back, hips, and tail regions of the spinal column. Parts of the lower hind limb were also recovered: a fibula, tibia, and 5 metatarsals. A femur (thigh bone) was found at the site but was too fragmented to collect.

*Agustinia ligabuei* was well known for its distinctive supposed armor plates, initially interpreted as a series of wide, vertical spikes and plates down the center of its back, somewhat like the unrelated *Stegosaurus*. However, further study of the poorly preserved fossil material showed that these "plates" were in fact more likely to be fragments of ribs and hip bones.

Aside from the supposed armor, very little has been described of the anatomy of *Agustinia*. A fibula (lower leg bone) has been recovered that is about 3 feet (895 mm) long. When compared to the same bone in related dinosaurs, this indicates that *Agustinia* may have been about 50 feet (15 meters) long. However, the remains are incomplete and do not appear to have many distinctive characteristics which can be used to separate it from other sauropods. With the supposedly distinctive armor discredited, some authors have considered *Agustinia* a *nomen dubium*, based on remains not adequate to compare with related dinosaurs.

Because of its supposedly unusual armor, *Agustinia* was originally assigned to its own family, Agustiniidae (Bonaparte, 1999). This family name has not come into wide acceptance. *Agustinia* is difficult to classify because of its fragmentary nature, and because it exhibits features of both diplodocoid and titanosaurian sauropods. What few distinctive features do exist in the only known specimen suggests it is a member of the clade Somphospondyli, but it is not possible to determine its relationships with any more accuracy beyond that.

## Dinosaur Earth Description

Agustinia may have been the most heavily armored sauropod, or long-necked plant eater, that ever lived. It looked a bit like a mix of Stegosaurus and Apatosaurus. Agustinia had long, sharp spikes on its back and neck and probably had other pieces of bony armor plates on its back. Because only part of this dinosaur has been discovered, scientists still don't know what family it belonged to. Some think it was an early member of the titanosaur family, which includes many of the Cretaceous sauropods from South America. Since only part of this dinosaur has been discovered, it isn't known how big it was, but it was probably at least 50 feet (15 m)
long. Discovered in 1996, Agustinia is still searching for a family. It has been linked to both the titanosaurs and the rebbachisaurs. The feet are very much like those of titanosaurs. The spikes of this sauropod seem to be very
pronounced and it also has flatter plates like those of a stegosaur.