25. A dinosaur covered in porcupine spines & the earliest fossil cloaca

The idea that dinosaurs were all scaley beasts got a massive challenge in 2000s when a variety of feather-like structures were found in fossils in China and other places. An even greater diversity of weird coverings have been found since then, most recently an iguanodontian covered in spines. This week we take a look at the porcupine looking Haolong dongi and what this means for dinosaur evolution. We also take a look some amazing trace fossils from the Permian of Germany, so detailed they even show the scales of an early reptile, including its cloaca. That's right, an improbable fossil butthole. Two tales of suprising scales. 

This week's papers are "Cellular-level preservation of cutaneous spikes in an Early Cretaceous iguanodontian dinosaur" by Jiandong Huang and colleagues published in Nature Ecology & Evolution in February 2026 https://doi.org/10.1038/s41559-025-02960-9 and "The earliest reptile body impressions with scaly skin" by Lorenzo Marchetti and colleagues published in Current Biology in March 2026. 

Wide screen artwork by Fabio Manucci.