Episode 416: Steve Brusatte on how mammals survived dinosaurs. Plus news from SVP including a great sauropod skull from the Antarctic, a bunch of dinosaur embryos, how the unique skin of sauropods may have helped keep them cool, and way more.

News:

• The Dinosaur Technical Session from the Society of Vertebrate Paleontology 2022 annual meeting source

Interview:

Steve Brusatte, a paleontologist, paleontology advisor for Jurassic World, and author of The Rise and Fall of the Dinosaurs, and more recently The Rise and Reign of the Mammals

Sponsors:

For 75 years The Folio Society has been turning books into works of art. They currently have special editions of Jurassic Park, The Lost World, and most recently The Rise and Fall of the Dinosaurs. The Rise and Fall of the Dinosaurs includes 32 pages of fossil photos, an 8-page full-colour gatefold illustration, and a large two-sided fold-out colour map.  Get the perfect gift for the Dino-lover in your life at foliosociety.com

The dinosaur of the day: Bruhathkayosaurus

• Titanosaur sauropod that lived in Late Cretaceous in what is now India (Kallamedu Formation)
• Probably looked like other sauropods, with a bulky body, long neck, and long tail
• Holotype found in 1978 and includes hip bones, partial leg bones, part of the arm, and a tail bone
• Fossils from the Kallamedu Formation are not well preserved. Monsoon season, with sands and clays from the formation, saturate them with water. Then in the dry season, fossils may expand in the day and contract at night. This makes the fossils fragile
• P. Yadagiri and K. Ayyasami described Bruhathkayosaurus in 1987
• Fossils started “disintegrating in the field jackets and crumbled to dust before reaching the repository of the Geological Survey of India, Hyderabad”, according to Saurabh Pal and Krushnan Ayyasami in 2022
• Said the fossils from the Kallamedu Formation are “very friable in nature”
• Fossils in the soft sandstone get water-saturated during monsoon season and dry in the summer when it’s intensely hot, which contributes to the “crumbly nature of the bones”
• (Holotype no longer here, similar to Amphicoelias, which we covered in episode 413)
• Original description had a few line drawings and photographs of the fossils at the dig site, and there were not many descriptions of its unique features
• Some researchers thought the fossils were petrified wood because of the large size, and some thought the find was a hoax
• Originally thought to be a carnosaur theropod, similar to Allosaurus
• In 1995 Chatterjee re-analyzed the fossils and found Bruhathkayosaurus to be a titanosaur
• Later studies found Bruhathkayosaurus to be an indeterminate sauropod or nomen dubium
• In 2022 Pal and Ayyasami reviewed the material and found the skeleton was real and Bruhathkayosaurus was probably valid
• Thought Bruhathkayosaurus to be a sauropod based on the fossils “exceptionally large dimensions”
• H. F. Blanford was the first to report large dinosaur bones from the formation, in 1862
• In 1929 Matley described some large bones and suggested they were from a titanosaur, “although he was not able to extract any bones, even with the greatest care” (they were very fragmentary)
• Yadagiri and Ayyasami found more large bones in 1987 and described Bruhathkayosaurus
• More sauropod fossils were found in the same area, including a titanosaur egg
• Lots of marine sediments in the formation, but there are some areas with vertebrate fossils, including dinosaurs
• So there is evidence there were sauropods in the area
• Pal and Ayyasami also talked about an additional photograph that was never published that shows the tibia bone of Bruhathkayosaurus in a plaster jacket (same tibia as the one in the other photos that showed it in the field)
• Tibia measurements show it was gracile and similar to sauropod tibia
• Tibia was 200 cm (about 78 in) long, about 29% larger than the tibia of Argentinosaurus
• Photos and diagrams of the ilium and tibia, but not the other fossils found
• Ilium was 120 cm (about 47 in) long, about 11 cm (about 4 in) smaller than the ilium of Dreadnoughtus
• The proportions of the ilium and tibia may mean they were not from the same individual, or even the same species
• Drawings of the ilium bone also show a feature found in theropod dinosaurs
• Estimated to be about 100 ft or 30 m long, based on illustration in the paper which is based on the tibia bone (a little bigger than a blue whale)
• Type species is Bruhathkayosaurus matleyi
• Genus name means “huge bodied lizard”
• Genus name comes from the Sanskrit word Bruhathkaya, meaning “huge body”
• Species name “matleyi” is in honor of Charles Alfred Matley, a paleontologist who found many fossils in India
• Other dinosaurs that lived around the same time and place include abelisaurids, carnosaurs, sauropods, stegosaurs, titanosaurs, troodontids

Fun Fact:

To precisely model joints moving you need 6 degrees of freedom (3 dimensions and 3 “translations” of the bones away from the joints).

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