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Fossil Discovery Challenges Ant-Eater Theory of Alvarezsaurids

3/9/2026

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Summary

Story summary

A fossil of Alnashetri cerropoliciensis challenges the idea that alvarezsaurids were ant-eaters, suggesting this species hunted insects and small mammals.
The fossil was found in Argentina's Río Negro Province and dates to circa 90 million years ago, the most complete alvarezsaurid skeleton in South America.
Skull and limbs are missing, but the skeleton indicates a subadult weighing about 700 grams and approaching sexual maturity.

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Story summary

A fossil of Alnashetri cerropoliciensis challenges the idea that alvarezsaurids were ant-eaters, suggesting this species hunted insects and small mammals.
The fossil was found in Argentina's Río Negro Province and dates to circa 90 million years ago, the most complete alvarezsaurid skeleton in South America.
Skull and limbs are missing, but the skeleton indicates a subadult weighing about 700 grams and approaching sexual maturity.