Amargasaurus cazaui

Overview

Amargasaurus cazaui is a sauropod distinguished by paired, elongated neural spines above its neck. Structures branching from the same neck vertebra create a distinctive outline. This dinosaur is studied through both the outer shape and internal tissue of its bones.^[1][2]

Key facts

Research has continued into whether the structures above the neck were horn-like or connected by a membrane. A bone-tissue study supported a neck skin-membrane hypothesis rather than horny sheaths. Tiny tissue features influenced interpretations of the dinosaur’s larger outline.^[2]

Time and place

This is an Early Cretaceous sauropod, presented by museums as approximately 125 million years old. Type specimen MACN-N 15 came from the lower La Amarga Formation in present-day Neuquén Province, Argentina. Its unusual neck vertebrae can be explored within their geographic and temporal context.^[3][1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

The neural spines of the neck vertebrae are elongated and split into two branches. The original description covers neck, trunk, and limb material together. Museums give a body length of approximately 9 m, with the long structures above the neck shaping its appearance.^[1][3]

Habitat and reproduction

What covered the long bones above the neck in life? Histological researchers proposed a skin membrane based on neural-spine features. It is an intriguing example of inferring soft body coverings from bone.^[2]

Fossil discovery

The English translation of the original description records that Guillermo Rougier discovered type specimen MACN-N 15 in February 1984. This occurred during the eighth Patagonian paleontological expedition led by José Bonaparte. A field discovery led to the description of a new dinosaur.^[1][2]

References

1. Salgado·Bonaparte (1991). Original description of Amargasaurus cazaui. English translation by Harris·Lamanna (2003).
2. Study of cervical neural spine tissues in Amargasaurus
3. Amargasaurus cazaui
4. Carballido et al. (2017) — Patagotitan, a giant titanosaur

Research questions

How much of an animal’s outer surface can be inferred from fossil bone tissue? Different hypotheses about tissues covering bones are compared with their structure. Research on Amargasaurus shifts attention from its striking neck outline to information inside the bone.^[2]

Observation

Follow the long, branching spines above the neck vertebrae. Then examine the trunk and limbs together to see how strongly the unusual neck structures stand out in the overall outline.^[1]