Moreover, I think the fact that we were inching towards this conclusion before we could properly study the new fossil material also shows what can be done even with scarce data - new fossils are always illuminating but rigorous scientific research can still get results!

🧵 End.

Nanotyrannus was indeed a separate dinosaur to Tyrannosaurus, and not only that but the two specimens we have actually represent two species of Nanotyrannus! Just goes to show how much of a difference having good fossil material can be to advancing palaeontology.

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There was a lot of wrangling to get the new material into the hands of palaeontologists for study, but they finally did a few years ago, permitting the detailed examination that would decisively turn the debate. Thus, we had the Zanno & Napoli paper yesterday!

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However, more Nanotyrannus fossil material still could blow the whole debate wide open again, so the debate settled into a stalemate. That was until new material was finally found! - new material was finally discovered in the mid-2000s.

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New analytical methods, particularly in histology (study of biological tissue microstructures) & new statistical approaches of modelling growth curves across other tyrannosaurs saw the debate swing back & forth, but in recent years it seemed to slowly move towards Nanotyrannus being distinct.

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There were enough similarities to suggest a link with T. rex, but there were also big differences (e.g., the pointedly narrow snout), so what was this? A juvenile T. rex or another kind of #tyrannosaur?
With only a skull for study, it was difficult to really say with much certainty.

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Originally known only from skull material, Nanotyrannus was the subject of fierce palaeontological debate. Animals can dramatically change as they grow (e.g., see how we change from childhood to adulthood), so while this was obviously different from a typical T. rex, was it just a juvenile?

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Just goes to show how new #fossils can have a big impact on our understanding of ancient life & more broadly, how paleontological science advances!

Here’s a nice news article on the paper & its implications for this longstanding debate in vertebrate #paleobiology ⬇️

www.nature.com/articles/d41...

Isotopic analysis of Megacerops tooth enamel revealed that it likely favoured moist environments, such as wet forests. Its teeth also show that it was a browsing herbivore, with teeth shaped for processing leafy vegetation 🍃

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#Brontotheres were among the first really big mammals to evolve, occupying large browser niches 🍃 in forest environments 🌳 Consequently, they diversified during the #Eocene when very warm climates & forest habitats prevailed ☀️

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#Megacerops likely stood up to 8 ft tall at the shoulders, making it one of the largest herbivores of its time. It lived ~38-33 million years ago during the #Eocene epoch - a time when mammals were really coming into their own and diversifying.

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