Episode 556: Updates on the Origins of Dinosaurs. Two new dinosaurs from the middle of the Triassic: the theropod Anteavis and the sauropodomorph Huayracursor. Plus our reviews of several TV shows, movies, and books including Walking with Dinosaurs.

News:

• We not yet have found the earliest dinosaur fossils, but they may be in the Amazon and areas by the equator in South America and Africa source
• Dinosaurs may have originated in South America, and then moved simultaneously to the east and north source
• There’s a new very early theropod dinosaur, Anteavis crurilongus source
• A nearly complete skeleton from a Triassic sauropodomorph, Huayracursor jaguensis source

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The dinosaur of the day: Ornithopsis

• Titanosaur sauropod that lived in the Early Cretaceous in what is now England (and possibly also Germany)
• As a titanosaur, was large, walked on all fours, had a long neck that it kept upright, a small head, and a long tail
• Has been compared to Giraffatitan, and based on that, estimated to be between 52 to 59 ft (16 to 18 m) long
• Known from a vertebra
• Ornithopsis vertebra has large cavities (for the air sacs), and is narrow, tall, with a ridge on the underside)
• Type and only species is Ornithopsis hulkei
• Named by Harry Seeley in 1870
• Genus name means “bird-likeness”
• Species name in honor of his colleague John Whitaker Hulke
• Lots of history with the fossils considered to belong to Ornithopsis (and then often, later considered to belong to another species)
• Started with Gideon Mantell describing fossils found in the Tilgate Forest from the Early Cretaceous Wealden Formation, in 1833, which included a bone he thought came from the skull of Iguanodon. Richard Owen in 1854 agreed but also said it could be part of a skull bone from the theropod Streptospondylus or the sauropod Cetiosaurus. Specimen number is R2239 (now NHMUK PV R 2239 because it’s at the Natural History Museum in London, it was purchased by the museum shortly after being described)
• In 1870, Harry Seeley described specimen NHMUK PV R 28632, which was a similar bone to the one Gideon Mantell had described
• This one was found on the Isle of Wight, and Mantell purchased it for the British Museum, now Natural History Museum, in 1853
• So now there were two vertebrae (including the one Mantell had described), and Seeley noticed that they had air sacs, similar to what’s in pterosaur and modern bird bones
• Seeley wrote in 1870: “The two vertebrae to which I would here call attention are in the British Museum; other remains allied to them were shown to me with much courtesy by the Rev. Mr. Fox, of Brixton. From these materials I am led to infer the existence of a new order of animals”
• He wrote he considered them to be from the same animal (similar in size, didn’t know of any other animals from the area)
• One vertebra from the lower part of the neck, the other from the lower part of the back
• Estimated it was at least 10 to 12 ft long, with a neck 4 to 5 ft long (presumed to have 7 cervical vertebrae)
• Considered the dinosaur to be between pterosaurs and birds, and maybe a dinosaur
• He wrote: “Both vertebrae agree in being constructed after the lightest and airiest plan, such as is only seen in Pterodactyles and birds”
• Seeley ended his description with: “I have made this note, not as a sufficient description of the specimens to which it relates, but in the hope that other parts of this and allied animals may be made available for scientific description by those collectors who possess them, and that they will so make known a group of animals as marvellous in size and organization as any which have enriched the records of paleontology. With the fossil I would associate the name of my friend Dr. Hulke, chronicling the species as Ornithopsis hulkei”
• In 1875 Richard Owen re-examined the fossils when he described multiple species of his now dubious genus Bothriospondylus (a possible sauropod from Late Jurassic in what is now England)
• He considered Gideon Mantell’s vertebra to be closer to Bothriospondylus than any flying animal as Seeley had thought. Owen renamed Mantell’s specimen Bothriospondylus elongatus
• For Seeley’s vertebra, Owen named it Bothriospondylus magnus (didn’t think the two vertebrae Seeley had described were from the same taxon)
• Owen also disagreed with Seeley that the vertebrae were open and light and showed a relationship to birds and pterosaurs, and suggested his new Bothriospondylus name should have priority over Ornithopsis
• The next year, 1876, Owen reassigned Bothriospondylus magnus to Chondrosteosaurus, a sauropod that lived in the Early Cretaceous in what is now England (Wessex Formation)
• In 1879 Hulke described more sauropod fossils from the Wealden and re-examined what Owen and Seeley had suggested
• Hulke said Seeley’s vertebra was the type specimen of Ornithopsis hulkei, which made Bothriospondylus magnus and Chondrosteosaurus magnus junior objective synonyms
• Hulke also mentioned that Owen saying the name Ornithopsis was misleading was false, because the vertebrae were lightly constructed, whether or not it showed a relationship to pterosaurs and birds
• Hulke also referred some other dinosaurs to Ornithopsis as junior synonyms (including Eucamerotus, a sauropod he had named)
• In 1995 William Blows found most of the sauropod fossils from the Wealden were dubious or intermediate, but said the type vertebra of Ornithopsis was unique, and it was valid (based on compression and a ridge)
• A fragmentary back bone (dorsal vertebra) was found in Germany in 2023 and referred to Ornithopsis sp.? but it is only tentatively referred (not preserved well enough to know)
• There were a number of additional Ornithopsis species named over the years, but they’ve been reassigned or considered indeterminate
• One is now Amanzia, which was named in 2020 (we covered as a news item in episode 279, titled “Traces of DNA in dinosaur cartilage”)

Fun Fact:

There’s a growing field of “paleo-inspired robotics”

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