The Big Dinosaur Podcast

Episode 374 is all about Spinophorosaurus, a sauropod from the Middle Jurassic of Niger that was originally thought to have a Stegosaurus-like spiky tail.

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In this episode, we discuss:

News:

• Stegouros, the ankylosaur we said had an “axe-like tail”, is better described as a macuahuitl tail source
• A new sauropodomorph, Issi saaneq, was found in what is now Greenland source
• A new study showed the ankylosaur Struthiosaurus had a poor sense of hearing and probably moved slowly source
• The Mace Brown Museum of Natural History in Charleston, South Carolina is offering a new paleontology scholarship source
• Frisco, Texas is building a new library, and it will include a life-sized model of a T. rex skeleton source
• Sir David Attenborough has a new documentary coming out later this year, called “Dinosaurs: The Final Day” source

The dinosaur of the day: Spinophorosaurus

• Basal sauropod that lived in the Middle Jurassic in what is now Niger (Irhazer Shale)
• Looked like other sauropods, bulky with a long neck and tail, on four legs (had a somewhat upright posture)
• Three specimens found
• One of the most complete known basal sauropods
• Subadult estimated to be around 43 ft (13 m) long, and the paratype estimated to be about 46 ft (14 m) long
• Estimated to weigh about 7 metric tons
• Had a short, deep, broad braincase
• Had spatulate (spoon shaped) teeth
• Had 13 neck vertebrae
• Neck vertebrae similar to Jobaria and Cetiosaurus
• Had small air-filled internal chambers in the dorsal vertebrae
• Air sacs are known in much later sauropods
• Had a rigid spine
• Neural spines were wrinkled
• Had a robust pelvis
• Had a strong, rigid tail
• Tail had more than 37 caudal vertebrae
• Chevrons in the front of the tail were blade-like
• Chevrons in the back of the tail were rod-like
• Originally thought to have spiked osteoderms at the end of the tail
• Right supposed osteoderm was larger than the left and a little different in shape, so they probably did not form a pair
• Tail spikes, when they were thought to be spikes, were thought to be large and bony near the end of the tail, arranged in a similar way to Shunosaurus (a sauropod that lived around the same time in what is now China)
• In 2012, Emanuel Tschopp and others found that the tail spikes were somewhat L-shaped and more like the L-shaped bones found at the Howe Quarry in the Morrison Formation than the tail spikes of Shunosaurus. Also they weren’t as rugose/wrinkled compared to other dinosaurs’ osteoderms. The L-shaped elements of Spinophorosaurus were a bit broader than the L-shaped elements from Howe Quarry, and had a triangular outline. And they found broken edges, so it’s possible the pair were the same size. Last, they were found below the scapula (shoulder blade), so suggested they were clavicles
• Type species is Spinophorosaurus nigerensis
• Described in 2009 by Kristian Remes and others
• Genus name means “spine bearing lizard”, based on what was thought to be spiked osteoderms on the end of the tail (later thought to be clavicles)
• Species name refers to the Republic of Niger
• A couple individuals collected in 2006 and 2007 at the Rural Community of Aderbissinat
• A juvenile was later also assigned to Spinophorosaurus
• Lots of dinosaurs were found in Niger in the 1960s and 1970s
• Paul Sereno excavated there between 1999 and 2003 and found Jobaria and Afrovenator
• In 2003, the PALDES project (Paleontología y Desarrollo – “Palaeontology and development”) excavated the area, with the goal of combining paleontological research with a developmental program (improving infrastructure, education, and promoting tourism)
• In 2005, Ulrich Joger and Edgar Sommer were exploring the area, and locals told them about some large bones in a new locality. They found a rounded bone tip coming out of the surface, which turned out to be a complete femur of the holotype of Spinophorosaurus (also found a shoulder blade and a vertebra). Fossils were in hard, brittle siltstone, and removed with light blows from hammers
• Worked with more locals and found most of the specimen in two days, which was mostly complete (in a death pose)
• In a photo of the holotype at the dig site, it looks like the fossil dig sites at museums, where you brush away dirt and there’s a (nearly) complete dinosaur
• They didn’t have the right equipment or permits, so they covered the fossils with debris to protect it and went back to Germany, with plans to do a full excavation via the Braunschweig museum
• Got a permit in 2006, and the plan was in exchange, the museum would build a new school in the area
• Also got sponsors, and the project was called “Projeckt Dino”
• Around the same time, the PALDES team from Spain was working in the area
• The mayor of Aderbissinat, Mohamed Echika, had given them permission to excavate the skeleton Joger and Sommer had been working on, and the skeleton ended up being shipped to Spain, without the German team knowing (they found an empty dig site)
• The German team ended up finding the paratype specimen
• Difficult excavation, not enough water (some people helping to dig fainted); temperatures got to 109–113 °F (43–45 °C)
• After nearly a week, all but two of the people on the team were sick with diarrhea and circulation problems
• Not much shade when digging
• Also a few sandstorms, that were described as peeling their skin
• Team finished on April 3, and Echika told them about what happened to the first skeleton. To make up for it, he led them to another fossil site, where they found the back end of possibly a Jobaria skeleton, but they had to leave it in the field until the next season (the PALDES team cancelled their plans to excavate, after the outbreak of the Tuareg rebellion from 2007 to 2009)
• Worked together with the local Aderbissinat community, comprised of people of various cultures (Tuareg, Hausa, and Fulani people)
• Dig was organized by a local Tuareg partner Ahmad Bahani and Tuareg Chief and Mayor of the village Tadibene Mohammed Echika
• Dig happened during a civil war, and they were protected by Mayor Mohammed Echika and the army
• Also lots of snakes, scorpions, monitor lizards, while digging (one person on site was a herpetologist so they knew what to do if bitten by a venomous snake). At night they used flashlights and went snake hunting
• Also found petrified wood, conifers, crocodile teeth, and fish scales (area was swampy and wet when Spinophorosaurus lived)
• Both the German (Braunschweig Museum) and Spanish (Elche museum) teams worked together to describe the dinosaur
• Took 2.5 years to prepare the paratype
• Paratype was about 70% complete, so the holotype helped fill in the remaining pieces
• Between the two specimens, most of the bones in the skeleton are known
• No forearms or hands found
• Holotype includes a braincase, parts of the skull, and most of the skeleton
• Paratype includes a partial skull and incomplete skeleton
• Specimens managed by the Musée National d’Histoire Naturelle, Niamey, Niger (returned after being on exhibit briefly and 3D printing the skeleton)
• First sauropod to have skeleton 3D printed
• In 2012, Adrián Páramo and Francisco Ortega described a small sauropod that was found near the two Spinophorosaurus specimens. Had 14 vertebrae, including all the neck vertebrae and some back vertebrae, which were smaller compared to the other specimens and also parts weren’t fused, so considered to be a juvenile Spinophorosaurus
• Dinosaur tracks found near the Spinophorosaurus skeletons, including six footprints from a medium sized sauropod and 120 two-toed theropod footprints (possibly by swimming theropods, which may be why one toe didn’t leave a mark)
• Lots of similarities between Spinophorosaurus and Middle Jurassic Eurasian sauropods, like Shunosaurus and mamenchisaurids (similarities in the vertebrae and humerus), and lots of differences between Spinophorosaurus and Lower and Middle Jurassic South Gondwanan sauropods (shape of neural spines, humerus, vertebrae)
• Spinophorosaurus helps show that features thought to be in derived sauropods found in East Asia are more like ancestral traits (plesiomorphic) in eusauropods, so there may be a connection between sauropods from the Jurassic in North Africa, Europe, and East Asia
• Important sauropod development may have happened in what is now North Africa
• Area was near the equator and wet in the summer, with lots of plants
• In 2012, Fabien Knoll and others looked at the braincase of Spinophorosaurus
• Did not have reduced vestibular apparatuses, sensory apparatus in the inner ear, which may mean it was important for vision and coordinating movements between the eyes, head, and neck
• Benjamin Jentgen-Ceschino and others in 2018 reported a probably pathology in Spinophorosaurus due to injury
• Found Spinophorosaurus had fast growing bone tissue
• In 2015, Vidal and others made a 3D model to study how Spinophorosaurus moved and found it couldn’t move its tail much (had overlapping chevrons, like dromaeosaurs and ankylosaurs)
• In 2020, Daniel Vidal and others looked at similarities between giraffe and sauropod necks as they grew up
• Looked at the specimens of Spinophorosaurus (they were different ages), as well as an adult and newborn giraffe
• CT scanned all the bones
• Both Spinophorosaurus and giraffes get more flexible necks as they grow
• Found that a subadult Spinophorosaurus could move its neck more than Plateosaurus and other previously analyzed sauropods, “enabling its neck to engage in many different postures unattainable by other sauropods”
• Found Spinophorosaurus was probably a high browser, like giraffes, based on the relatively long humerus, and narrow snout, and having an overall range of motion similar to a giraffe. But found, that Spinophorosaurus was as flexible in the neck as a giraffe because it had almost twice the number of neck vertebrae of a giraffe (not as much flexibility in between vertebrae as a giraffe)
• Based on its skeleton, could “browse on vegetation at nearly three times the height of its shoulders”
• To drink water, Spinophorosaurus would needed to have splayed like a giraffe
• Found Spinophorosaurus to have a more vertical posture than before, with its tall shoulders and an elevated neck “well above shoulder level”
• Based partially on having the 20° wedged sacrum (vertebrae between the hips)
• Spinophorosaurus’s snout was about 16.4 ft (5 m) above the ground
• SVPow agreed with Vidal and others about their reconstruction, and how Spinophorosaurus had wedged sacrum so it had a more inclined torso and neck
• That means the tail and torso are not parallel with each other
• However, also mentioned that bones are not enough to show how vertebrae articulated, and models need to incorporate intervertebral cartilage (which Vidal and others mentioned, but said that since we don’t really know how much cartilage there was, so it’s likely we won’t ever know)
• In 2018, Vidal and others tested hypothetical mating postures to see if Spinophorosaurus performed a “cloacal kiss”, “backwards mating”, or the male mounting from behind. Found the male could mount the female from behind while resting its front legs on the back (tail was flexible enough to get out of the way), but they could not perform a “cloacal kiss” unless they did “backwards mating” where they approach each other backwards and have their tail flexed sideways
• A model of Spinophorosaurus outside the Braunschweig Museum is nicknamed “Namu”, after the museum’s name

Fun Fact: There are a lot of ways of prey species to increase their odds of surviving, but predator satiation might be the most interesting.

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