A Century After Its Discovery: Triassic Specimen Found To Be Early Relative of Pterosaurs

Early Pterosaur Scleromochlus taylori

Life reconstruction of Scleromochlus taylori by Gabriel Ugueto. Credit: Gabriel Ugeuetto

Over 100 years ago a tiny Triassic fossil reptile was first discovered in the northeast of Scotland. Now, a new analysis has revealed it to be a close relative of the species that would become pterosaurs – iconic flying reptiles of the age of the dinosaurs.

The research, published on October 5, 2022, in the journal Nature, was carried out by a team of scientists led by Dr. Davide Foffa, a Research Associate at National Museums Scotland, and now a Research Fellow at the University of Birmingham. Working together with colleagues at Virginia Tech, the team used Computed Tomography (CT) to provide the first accurate whole skeleton reconstruction of Scleromochlus taylori.

Pterosaur, from Greek pteron and sauros, means “winged lizard.” The earliest known pterosaurs lived around 220 million years ago in the Triassic period, and the last ones died about 65 million years ago at the end of the Cretaceous period. Although pterosaurs were contemporaries of dinosaurs, pterosaurs are non-dinosaurian reptiles. They ranged from pigeon-sized with a wingspan of 18 inches to ultralight-airplane-sized Quetzalcoatlus with a wingspan of 36–39 feet. Exceptionally well-preserved fossils have shown that pterosaurs were covered with hair.

The results reveal new anatomical details that conclusively identify it as a close pterosaur relative. It falls within a group known as Pterosauromorpha, comprising an extinct group of reptiles called lagerpetids together with pterosaurs.

Living approximately 240-210 million years ago, lagerpetids were a group of active reptiles that were relatively small (cat or small dog-sized). Schleromochlus was smaller still at under 8 inches (20 centimeters) in length. The results support the hypothesis that the first flying reptiles evolved from small, likely bipedal ancestors.

The finding settles a century-long debate. There had previously been disagreement as to whether the reptile, Scleromochlus, represented an evolutionary step in the direction of pterosaurs, dinosaurs, or else some other reptilian offshoot.

The fossil of Scleromochlus is poorly preserved in a block of sandstone, which has made it difficult to study in sufficient detail to properly identify its anatomical features. The fossil is one of a group known as the Elgin Reptiles, comprising Triassic and Permian specimens found in the sandstone of the Morayshire region of northeast Scotland around the town of Elgin.

The specimens are held mostly in the collections of National Museums Scotland, Elgin Museum, and the Natural History Museum. The latter holds Scleromochlus, which was originally found at Lossiemouth.

The Permian and Triassic fossils discovered in sandstone deposits near the town of Elgin in Moray, Scotland, are known as Elgin Reptiles. Many of the specimens are kept in the Elgin Museum, while others are kept in the Hunterian in Glasgow and the National Museum of Scotland in Edinburgh. They are significant both historically and scientifically. The Elgin Reptiles include the dicynodont Gordonia, the dinosauriform Saltopus elginensis,and the pareiasaur Elginia.

Dr. Foffa said: “It’s exciting to be able to resolve a debate that’s been going on for over a century, but it is far more amazing to be able to see and understand an animal that lived 230 million years ago and its relationship with the first animals ever to have flown. This is another discovery which highlights Scotland’s important place in the global fossil record, and also the importance of museum collections that preserve such specimens, allowing us to use new techniques and technologies to continue to learn from them long after their discovery.”

Professor Paul Barrett at the Natural History Museum said: “The Elgin reptiles aren’t preserved as the pristine, complete skeletons that we often see in museum displays. They’re mainly represented by natural molds of their bone in sandstone and – until fairly recently – the only way to study them was to use wax or latex to fill these molds and make casts of the bones that once occupied them. However, the use of CT scanning has revolutionized the study of these difficult specimens and has enabled us to produce far more detailed, accurate and useful reconstructions of these animals from our deep past.”

Professor Sterling Nesbitt at Virgina Tech said: “Pterosaurs were the first vertebrates to evolve powered flight and for nearly two centuries, we did not know their closest relatives. Now we can start filling in their evolutionary history with the discovery of tiny close relatives that enhance our knowledge about how they lived and where they came from”

Reference: “Scleromochlus and the early evolution of Pterosauromorpha” by Davide Foffa, Emma M. Dunne, Sterling J. Nesbitt, Richard J. Butler, Nicholas C. Fraser, Stephen L. Brusatte, Alexander Farnsworth, Daniel J. Lunt, Paul J. Valdes, Stig Walsh and Paul M. Barrett, 5 October 2022, Nature.
DOI: 10.1038/s41586-022-05284-x

In additional to National Museums Scotland, the Natural History Museum and Virginia Tech, the study also involved the Universities of Birmingham, Bristol and Edinburgh as well as the Chinese Academy of Sciences.

2 Comments on "A Century After Its Discovery: Triassic Specimen Found To Be Early Relative of Pterosaurs"

  1. Pterosaurs is a flightless dinosaur and very aquatic dinosaur its skin is smooth and web toes like duckbill dinosaur finger it’s a sting ray mimic .pterosaur clearly is a dinosaur it has serrated teeth and unique occified tendon with duckbill dinosaur and a tail end like birds and Tyrannosaur deinocheirus .sclermochlus is allso a dinosaur the ankle is fuse to tibia like pterosaur but it is not a pterosaur what it is they know because I know it’s a proterochampsa .proterochampsa ankle is allso advance but even more advance than 4 finger dinosaur this is the reason I think tetanuran dinosaur did not come from 4 finger dinosaur .scleromochlus has 4 sacral vertebrae it is bipedal like the tyrannosaur the gator it was a poor sprawler it’s ankle fuse to tibia a very dinosaur feature that why gator ankle is not fuse to tibia it’s a good sprawler proterochampsa ankle is more advance 4 finger dinosaur it’s has tetanuran ankle these primitive dinosaur they are unique in having tetanuran dinosaur advance feature pterosaur too scleromochlus bipedalism is not like t.rex it did not walk on there toes like the greatest dinosaur ever live the gator scleromochlus has a human ankle like the gator calcaneal tuber .it’s a advance feature in dinosaur.

  2. Some say sclermochlus is a ornithosuchus and erpetosuchus and because of the wider tetanuran dinosaur skull that is not bird like .but teeth is too primitive a tuatara remnants teeth a archosauriformies teeth palate teeth found in eoraptor doswellii pterosaur proterochampsa .doswellii is allso a dinosaur because turtle unique low shell skin in thecodont only found in dinosaur .sclermochlus allso has hollow legs like the mesoeucrocodylia macelognathus .these primitive dinosaur are very close to tetanuran dinosaur and seem to answer the evolution question .early pterosaur has stiff tail a tetanuran feature later pterosaur become better swimmer so they have gator tail the gator tail is for swimming only .it’s a hybrid tail for bipedalism and swimming early dinosaur lack extreme bipedal tail found in tetanuran dinosaur .pterosaur allso lack kink snout this show it was advance reptile inside dinosaur early dinosaur herrerasaurus allso lack kink snout .kink snout is fish eating feature a early thecodont feature because early thecodont were a semi aquatic animal that why ceratosaurus still has gator tail and duckbill dinosaur. Thecodont means crocodilian teeth you see dinosaur was all ways a crocodilian and pterosaur too.the name archosaur is a fantasy with no scientific facts.pterosaur later got kink snout because it very aquatic dinosaur become a good fisher it’s nose move backwards like spinosaurus duckbill dinosaurs edmontosaurus a tetanuran feature.proterochampsa all ankle bones is fuse this show tetanuran is lot older .now to allosaur it’s really is a tyrannosaur I thought is just megalosaurian a little advance megalosaurian with a lot of miss mesoeucrocodylia feature even when shown all the evidence it’s hard when they are no sagittal crest but I know a trademark feature all tyrannosaur have this I was going use to show spinosauridae gator are the same animal because it is big in mesoeucrocodylia .it became side track because all good evidence I landing on this will take time but I know answer when allosaurus parietal fuse then fuse to frontal it’s a gator. on likely other thecodont have this feature in reptile the skull bone are a lot .and less fusion that why they know maniraptoran is a bird and not a dinosaur in mammal and birds is because bigger brain in reptile it’s a predator feature because the brain is small .allosaurus did not come from megalosaurian it’s a tyrannosaur it’s a primitive tyrannosaur the neck joint with advance megalosaurian is convergent evolution allso finger and arm movement .allosaurus best arm movement in dinosaur this show there is no link .

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