Episode 363 is all about Streptospondylus, one of the first dinosaurs discovered, but it wasn’t known to be a dinosaur until about 100 years after it was collected.
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In this episode, we discuss:
News:
- We discuss the Macroecology & Macroevolution and Education & Outreach sessions from the Society of Vertebrate Paleontology annual meeting source
- A 160 million year old dinosaur fossil was found on a construction site in Longchang city, Sichuan, China source
- A partial tyrannosaur skull nicknamed “Beautiful Nightmare” was found in North Dakota source
The dinosaur of the day: Streptospondylus
- Tetanuran theropod that lived in the Late Jurassic in what is now Normandy, France
- Looks like a typical theropod, with sharp teeth, powerful legs, and short arms
- Mid-sized
- Estimated to be 19.5 ft (6 m) long and weigh 1,100 lb (500 kg)
- Type species is Streptospondylus altdorfensis
- It’s one of the first named theropods, but very few people know about it. It has been called the “First binomial name that refers to a theropod”
- One of the first dinosaur fossils found and was technically the first dinosaur described, but wasn’t the first dinosaur named (wasn’t thought to be a theropod until 2001)
- Most of the fossils were part of Abbé Bachelet’s private collection in 1770, which ended up with Georges Cuvier in 1800
- Mostly found in Honfleur, France, and included cranial and postcranial fossils from two teleosaurs, and some theropod fossils
- Guersent sent the fossils to the Museum in Rouen, which led to Georges Cuvier having them
- In 1812 Cuvier added more fossils to the collection, fossils found in LeHavre and described in 1776 by Abbé Dicquemare
- Unclear where exactly the Bachelet Collection fossils were found, only known they were near Honfleur
- The full collection has never been published
- Some of the fossils associated with Megalosaurus (part of a pubis, tibia, astragalus and calcaneum)
- These fossils examined at the Muséum national d’Histoire naturelle, Paris, and those fossils probably found at the Vache Noires cliffs, dated Upper Callovian-Lower Oxfordian (Jurassic)
- In 1824 Cuvier referred some of the Honfleur fossils to two species of crocodilians based on the length of the snout (one was long, one was short), also talked about the differences in the two vertebral systems found in association with the skulls
- In 1825 Geoffroy Saint-Hilaire said, based on the cranial fossils, that both species were the crocodyliform Steneosaurus: Steneosaurus rostromajor (includes the skull) and Steneosaurus rostrominor (includes a complete mandible)
- These names therefore only applied to the cranial fossils, and not the postcranial fossils (vertebrae that Cuvier described)
- In 1832 Christian Erich Hermann von Meyer renamed the short snouted Steneosaurus rostrominor as Metriorhynchus geoffroyii (a marine crocodyliform) and the long snouted Steneosaurus rostromajor became his newly named species Streptospondylus altdorfensis
- Von Meyer include all the fossils Cuvier had described, and said that skull and vertebrae both belonged to Streptospondylus altdorfensis
- He also didn’t designate a type specimen
- This makes Streptospondylus a mix of theropod vertebrae and the type species of Steneosaurus rostromajor, which turned out to be a composite of parts from two different teleosaur species
- These parts of the skull eventually became Steneosaurus edwardsi in 1870 (named in 1866) and Metriorhynchus superciliosum in 1973 (named in 1853)
- In 2001, Ronan Allain said this means Streptospondylus is basically only known from postcranial fossils, and Streptospondylus altdorfensis is valid
- In 1842, Richard Owen said that Streptospondylus altdorfensis should be Streptospondylus rostromajor (keeping the original species name)
- In 1842, Owen also created Streptospondylus cuvieri (type species is part of a dorsal vertebra found in Chipping Norton in Oxfordshire, England, also referred a tooth and neural spine)
- Fossil has since been lost and according to Allain, Owen’s description of it “holds no scientific value”
- Allain said Streptospondylus cuvieri was a nomen dubium
- In 1861, Owen said the skulls and vertebrae from Honfleur were in a suborder for crocodiles
- Owen still considered Streptospondylus to be valid, but he started referring all material to Streptospondylus cuvieri and not Streptospondylus rostromajor (unclear why, he never explained)
- Other scientists from 1870 to 1923 also used the name Streptospondylus cuvieri
- Sometimes had mixups (Edward Cope named Laelaps gallicus in 1867 and Friedrich von Huene wrote about Megalosaurus cuvieri in 1909, which are junior synonyms)
- In 1964, Alick Walker said the Streptospondylus cuvieri material wasn’t from Honfleur and synonymized Streptospondylus altdorfensis with Steneosaurus rostromajor
- Walker also named new species Eustreptospondylus oxoniensis (genus name means “true Streptospondylus” and it’s a megalosaur from the Late Jurassic)
- Eustreptospondylus oxoniensis was found in 1870 in Oxford, England
- Skeleton referred to Megalosaurus bucklandi in 1890
- In 1905 and 1906 Franz Nopsca reassigned it to Streptospondylus cuvieri
- Odd, since the skeleton was nearly complete, and assigned to a species with very incomplete remains
- Walker in 1964 also referred the theropod material Cuvier had described as a new species, Eustreptospondylus divesensis
- Said the type species was a partial braincase Jean Piveteau described in 1923 that Piveteau had assigned to Streptospondylus cuvieri (found in the Vaches Noires cliffs in Normandy, France)
- Walker also included the fossils Owen had attributed to Streptospondylus cuvieri as Eustreptospondylus divesensis
- In 1977 Philippe Taquet and Samuel Welles said that the postcranial fossils Piveteau described and a nearly complete skeleton of Eustreptospondylus at the Oxford University Museum were two different genera: Piveteausaurus (an allosauroid they named in 1977) and Eustreptospondylus
- They only considered the partial braincase to be Piveteausaurus (genus name means “Jean Piveteau’s lizard”), not the postcranial fossils
- Allain also said there was nothing to indicate the vertebrae from Honfluer were the same taxon as Piveteausaurus
- Allain said Walker’s 1964 conclusions only made sense if Streptospondylus altdorfensis is a junior synonym of Steneosaurus rostromajor
- In 2001 Allain redescribed Streptospondylus and named a lectotype, which included vertebrae, part of the left pubis, part of the right fibula, the right astragalus, and the right calcaneum
- Also referred part of a left femur (described in 1890, not part of the Bachelet collection, unknown where it was found but has enough similarities)
- Found Streptospondylus altdorfensis to be valid, and that all material should be assigned to that species
- Also found Streptospondylus and Eustreptospondylus to be closely related and to be part of Megalosauroidea
- Genus name Streptospondylus means “reversed vertebra”
- Genus name refers to the vertebrae being different from typical crocodile elements
- Species name altdorfensis refers to teleosaur (marine crocodylomorphs) cranial fossils found in Altdorf, which Von Meyer thought were the same taxon as the fossils found near Honfleur
- Other names:
- Owen also named Streptospondylus major in 1842, Streptospondylus recentor and Streptospondylus meyeri in 1851, and Streptospondylus grandis in 1854 (fossils now thought to be iguanodont)
- In 2010 Gregory Paul informally renamed Magnosaurus, Streptospondylus nethercombensis, but most still consider Magnosaurus to be valid
- Magnosaurus and Streptospondylus have been found to be sister taxa
Fun Fact: There are over 400 taxa of theropods from the Mesozoic, making them the most diverse group of dinosaurs.
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