Argentinosaurus huinculensis

Argentinosaurus huinculensis is one of the strongest candidates for the largest land animals known, but it is also one of the least complete famous dinosaurs. The holotype represents a single individual and consists principally of giant dorsal vertebrae, part of the sacrum, a rib fragment and a slender lower-leg bone now interpreted as a fibula. No skull, teeth, neck, tail, complete limb or foot is known. Estimates near 30-35 metres and roughly 60-90 tonnes are reasonable working ranges, not direct measurements of a complete skeleton.

Its fossils occur between approximately 97 and 93.5 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The best anatomical evidence comes from the trunk. Several dorsal vertebrae have broad, tall neural arches, extensive internal air spaces and unusually enlarged accessory hyposphene-hypantrum articulations that reinforced adjacent vertebrae without making the back rigid. One reconstructed anterior dorsal vertebra reaches about 1.59 metres high. The preserved sacral region has strongly reduced central bodies surrounded by large internal chambers, and the rib fragment is hollow. The 1.55-metre limb bone described in 1993 as a tibia was subsequently reidentified as a slender fibula. Every other major body region in a full reconstruction is inferred from better-known titanosaurs.

• Enormous, highly pneumatic dorsal vertebrae
• Expanded hyposphene-hypantrum accessory joints reinforcing the back
• Anterior dorsal neural arches more than a metre across
• Partial sacrum with reduced central bodies and large internal air spaces
• Hollow, thin-walled dorsal rib fragment
• Long, comparatively slender fibula originally described as a tibia
• Skull, neck, tail, feet and most limb proportions unknown

Rancher Guillermo Heredia reported a giant bone at Las Overas, about eight kilometres east of Plaza Huincul in Neuquen Province. Museo Carmen Funes personnel recovered the first limb bone, and a Jose Bonaparte-led expedition excavated the associated vertebral and sacral material in the summer of 1989. Jose F. Bonaparte and Rodolfo A. Coria named Argentinosaurus huinculensis in 1993. The holotype, MCF-PVPH 1, remains in the vertebrate palaeontology collection of the Museo Municipal Carmen Funes.

Discovery credit: Guillermo Heredia, Museo Carmen Funes field team, Jose F. Bonaparte.

Naming authors: Jose F. Bonaparte, Rodolfo A. Coria.

The Huincul Formation records river channels, floodplains, wind-worked sediment and developing soils in the Neuquen Basin. The original description noted medium-energy fluvial deposits and abundant fossil tree trunks near equivalent levels. Argentinosaurus shared the broader formation with other sauropods and large theropods including Mapusaurus, but formation-level association does not prove that any named predator encountered the holotype individual.

As a titanosaur, Argentinosaurus was a four-legged herbivore that probably stripped vegetation with a small head and swallowed it with little oral processing. Its huge, air-filled skeleton would have reduced mass relative to solid bone, while columnar limbs and a restricted joint range supported slow, stable terrestrial locomotion. A 2013 computer simulation produced a plausible walking gait for an 83-tonne museum reconstruction, but the result tests that reconstructed model rather than a complete Argentinosaurus skeleton. No trackway, nest, herd accumulation or feeding trace is directly assigned to the species.

• The holotype comes from only one animal, despite the species often being illustrated as a herd.
• A reconstructed anterior back vertebra stands about 1.59 metres high.
• The first reported limb bone was called a tibia in 1993 but was later recognised as a fibula.
• The name combines Argentina with the Greek sauros, while huinculensis honours Plaza Huincul.
• A full museum skeleton is mostly comparative reconstruction because the skull, neck, tail and feet were never found.

A research repository is not necessarily a public exhibit. Loan and display status can change, so check with the institution before visiting.

1. 01
   The Paleobiology Database

   Open source
2. 02
   A new and huge titanosaur sauropod from the Rio Limay Formation (Albian-Cenomanian) of Neuquen Province, Argentina

   Jose F. Bonaparte, Rodolfo A. Coria · Ameghiniana 30(3) · 1993

   Open source
3. 03
   Giants and bizarres: body size of some southern South American Cretaceous dinosaurs

   Gerardo V. Mazzetta, Per Christiansen, Richard A. Farina · Historical Biology 16(2-4) · 2004

   Open source
4. 04
   March of the titans: the locomotor capabilities of sauropod dinosaurs

   William I. Sellers, Lee Margetts, Rodolfo A. Coria, Phillip L. Manning · PLOS ONE 8(10) · 2013

   Open source
5. 05
   Argentinosaurus: Dino Directory

   Natural History Museum, London

   Open source
6. 06
   Reopening of the Museo Carmen Funes in Plaza Huincul

   Government of Neuquen Province · 2019

   Open source
7. 07
   Giants of the Mesozoic

   Fernbank Museum of Natural History

   Open source
8. 08
   The accuracy and precision of body mass estimation in non-avian dinosaurs

   Nicolas E. Campione, David C. Evans · Biological Reviews 95(6) · 2020

   Open source