A newly discovered giant tyrannosaur bone from New Mexico’s Hunter Wash Member may rewrite the origin story of Tyrannosaurus rex, suggesting it first evolved in southern North America rather than the north.
🦖 Discovery Highlights
- Location: Hunter Wash Member, Kirtland Formation, San Juan Basin, New Mexico.
- Age: ~74 million years ago (Late Campanian period).
- Fossil: A massive tibia (shinbone), nearly 1 meter long and extremely robust.
- Estimated Size: The dinosaur weighed 4–5.9 metric tons, larger than other tyrannosaurs of its time.
🔬 Scientific Significance
The bone’s proportions suggest it belonged to Tyrannosaurini, the lineage that includes T. rex. This supports the “southern origins hypothesis”: giant tyrannosaurs first appeared in southern Laramidia (New Mexico, Texas, Utah) before spreading north to Montana and Canada.
The find highlights regional differences in Late Cretaceous ecosystems:
- North: Smaller tyrannosaurs like Albertosaurinae and Daspletosaurini.
- South: Giant tyrannosaurins, precursors to T. rex.
📊 Comparison Table
| Feature | Hunter Wash Tyrannosaur | Tyrannosaurus rex |
|---|---|---|
| Age | ~74 million years ago | 66–68 million years ago |
| Location | New Mexico (southern Laramidia) | North America (widespread) |
| Fossil Found | Tibia (shinbone) | Multiple skeletons |
| Length of Tibia | ~960 mm | ~1140 mm (largest) |
| Estimated Mass | 4–5.9 tonnes | Up to 10 tonnes |
| Significance | Possible early Tyrannosaurini | Apex predator of Late Cretaceous |
⚠️ Caveats
- The discovery is based on a single bone, so conclusions remain tentative.
- More fossils (ideally a full skeleton) are needed to confirm whether this was a new species, a giant Bistahieversor, or an early Tyrannosaurus.
- The find nonetheless provides critical evidence for the evolutionary path of tyrannosaurs.
Source: Sci.News
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