Dicynodonts survived multiple environmental upheavals & mass extinction events but finally met their end in the End-Triassic Mass Extinction (~201 Ma). Why they finally went extinct remains somewhat unclear - perhaps due to their increasing niche specialisation through the Late Triassic?

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#Ischigualastia was among the largest of known dicynodonts & one of the last, evolving in the Late Triassic as the group declined. Nonetheless, despite becoming rarer, these latest dicynodonts grew larger, with the youngest species, #Lisowicia being the largest (rhino-sized).

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#Dicynodonts were notably able to survive the worst mass #extinction event in history: the End-Permian event (~252 Ma). Despite this evolutionary bottleneck, they were able to diversify & regenerate a comparable level of diversity in the Triassic to their pre-extinction levels in the #Permian.

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These herbivores possessed a unique beaked jaw & jaw adductor muscle arrangement that produced powerful & efficient cropping bites. They also had a rolling jaw joint that enabled them to effectively break down plant matter when eating. It’s thought these features contributed to their success.

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#Dicynodonts were an ancient & successful group of #synapsids that lived from the middle of the #Permian to the end of the #Triassic. They were among the largest terrestrial animals of their time, only really surpassed when large dinosaurs began to evolve in the Late Triassic.

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This specimen was found on a 1964 expedition that took BYU's James A. Jensen & a Harvard team of paleontologists to the #Ischigualasto Formation of Argentina. This formation has yielded an amazing array of animal & plant fossils from the #Carnian stage of the Late #Triassic (237-227 Ma).

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#Stegosaurus is perhaps most known for the bony plates along its back. Their function is still unknown, but it has been proposed that they may been displays to help deter predators or attract mates. Or perhaps thermoregulation structures. Still much to learn about these #dinosaurs!

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Sophie is a #Stegosaurus stenops, a species found across the Morrison Formation in western USA 🇺🇸, with fossil found across Wyoming, Colorado & Utah. It lived during the Late #Jurassic period, around 150 million years ago, and was a herbivore (plant-eater) 🌿.

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It’s not actually known whether Sophie was a female as it’s very difficult to sex extinct animals, especially dinosaurs, when all we have are their bones. This specimen was named after the daughter of the donor who helped the NHMUK to acquire the fossils.

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Sophie was not yet an adult when she died, so despite being 5.5 metres long & 2.9 metres tall, she still had some growing left to do! It’s thought that not many #dinosaurs reached their max size as just surviving to adulthood was difficult (especially with all the larger predators about… ).

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Sophie was discovered in 2003 at Red Canyon Ranch in Wyoming, USA 🇺🇸. Her fossilised skeleton encompasses ~360 bones & is around 85% complete, making her perhaps the most complete #stegosaurus skeleton in the world. She was put on permanent display at the NHMUK 🇬🇧 at the end of 2014.

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