Episode 421: A raptor with preserved intestines. Plus a new aquatic dinosaur (that isn’t Spinosaurus), a pregnant T. rex, a dinosaur airlift, and more

News:

• Paleontologists discovered new dromaeosaur, Daurlong wangi, complete with part of the intestines! source
• A new non-avian dinosaur, Natovenator, with a streamlined body for swimming and hunting fish source
• The Auckland War Memorial Museum in New Zealand has two T. rex on display, and one of them may have been pregnant source
• Maximus, the T. rex skull, sold for a lot less than expected source
• Gary the Edmontosaurus was airlifted from Red Deer River valley in Alberta, Canada this summer source
• You can get an AR model of Scotty the T. rex via the Royal Saskatchewan Museum source
• The Hongkong Post is issuing six dinosaur stamps source

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This episode is brought to you by the Sternberg Museum of Natural History. They have amazing summer camps every year including field paleontology, paleoart, and virtual options. Find out more and sign up at https://bit.ly/camps23

The dinosaur of the day: Ostafrikasaurus

• Theropod that lived in the Late Jurassic in what is now Tanzania (Tendaguru Formation)
• Only teeth have been found
• No skull fossils found for Ostafrikasaurus
• But as a spinosaur, Ostafrikasaurus probably had a long, narrow snout. Probably also had a long tail, bulky body, and walked on two legs
• Estimated to be about 28 ft (8.4 m) long and weigh 1.15 tonnes
• Hard to estimate size based on the fragmentary fossils
• Fossils found between 1909 and 1912
• During the expeditions from 1909 to 1912, 230 isolated theropod teeth were found. One of them was assigned to Labrosaurus? stechowi in 1920 by Werner Janensch, who tried to identify all the teeth by classifying them into five types in a monograph in 1925
• In 2000, James Madsen and Samuel Welles referred the Labrosaurus? stechowi teeth to Ceratosaurus sp.
• Labrosaurus is now considered to be a synonym of Allosaurus
• In 2007, Denver Fowler suggested the teeth were spinosaurid teeth. Eric Buffetaut in 2008 also suggested they were spinosaurid teeth
• In 2011, Oliver Rauhut found Labrosaurus? stechowi to be dubious (no unique features) and referred the teeth found in the Tendaguru Formation as Ceratosaurus? stechowi
• Ostafrikasaurus named in 2012 by Eric Buffetaut, based on two teeth
• One of the two teeth is the holotype
• Holotype tooth is 1.8 in (46 mm) long, and has a curved front edge, with large serrations (larger than other spinosaurid teeth)
• Tentatively referred a second tooth. Both teeth are curved in the front but there are some differences in the ridges (which could be due to individual variation) and the two teeth came from different parts of the Tendaguru Formation
• Hard to name dinosaurs based on teeth, but Buffetaut said that theropod teeth, and in particular spinosaurid teeth, can have unique enough features to name a dinosaur (based on features such as ornamentation)
• Teeth looked similar to the teeth of Baryonyx
• Ornamentation on the teeth have similarities to lots of different theropods, including Ceratosaurus and Coelophysis
• A 2020 study of teeth from the Tendaguru Formation found Ostafrikasaurus to be a ceratosaurid
• Fowler suggested ceratosaur and spinosaur teeth were connected, though Buffetaut didn’t agree
• Buffetaut described Ostafrikasaurus as an early spinosaurid theropod
• Teeth had strong ridges (Baryonyx and close relatives, including spinosaurid teeth found in Asia, also had strong ridges, which is why the teeth are thought to be spinosaurid)
• Type species is Ostafrikasaurus crassiserratus
• Genus name comes from [Deutsch]-Ostafrika, which means “German East Africa lizard”
• Species name means “thick” and “serrated” and refers to the teeth
• Enamel on the tooth is “finely wrinkled”
• Large serrations on the teeth
• Helps show that spinosaur teeth becoming more conical and less serrated as they evolved
• May mean that earlier spinosaurids had larger serrations on their teeth and they evolved to have smoother teeth that were also more straight (less curved)
• One of the oldest known spinosaurid fossils
• Helps show spinosaurids may have lived around the world before Pangaea broke up
• Buffetaut suggested spinosaurids were widespread early on, based on spinosaurids being found in Asia and Asia probably was separated from the other continents in the Late Jurassic and Early Cretaceous
• Lots of other spinosaurs described are from the Early Cretaceous, so much later than Ostafrikasaurus
• In 2016, Alejandro Serrano-Martínez and others described a possible spinosaurid tooth found in Niger. Tooth is probably from the Middle Jurassic, about 14 million years earlier than Ostafrikasaurus (which would make it the oldest known spinosaurid fossil)
• Lived in a subtropical to tropical environment, with dry and rainy seasons
• Other dinosaurs that lived around the same time and place include sauropods such as Giraffatitan, stegosaurs such as Kentrosaurus, and other theropods such as abelisaurids, and possibly Torvosaurus
• Other animals that lived around the same time and place included pterosaurs, crocodyliforms, fish, and mammals

Fun Fact:

Terrestrial animals have returned to the water (to become secondarily aquatic) over 30 times.

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