The Big Dinosaur Podcast

Episode 226 is all about Kaatedocus, the smaller cousin of Diplodocus and Barosaurus.

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In this episode, we discuss:

News:

• A new basal ornithopod with skinny arms, Mahuidacursor lipanglef, was described in Argentina source
• A hadrosaur was found in Montana with marks showing it was probably chewed on by a juvenile T. rex source
• Tracks from the Middle Jurassic of China appear to be the first evidence of quadrupedal theropod walking source
• Several institutions in New Mexico are working together this spring to photograph, scan, map, and model the Clayton Lake Dinosaur Tracksite source
• Dinosaur Journey Museum in Fruita, Colorado, has a new 6ft 4in Apatosaurus femur on display source
• The Natural History Museum at Tring in the UK has a new, free exhibition, that shows off the dinosaurs of the British Isles source
• The U.S. Postal Service is coming out with new T. rex stamps this year source
• The Canadian Mint has a new, limited edition glow in the dark dinosaur coin of a hatching Hypacrosaurus source

The dinosaur of the day: Kaatedocus

• Sauropod that lived in the Late Jurassic in what is now Wyoming, US (Morrison Formation)
• Looks similar to Diplodocus and Barosaurus
• Classified as a Diplodocinae
• Estimated to be about 46 ft (14 m) long
• Lived earlier than Diplodocus and was smaller than Diplodocus, and helps with understanding the evolution of diplodocids
• Also found further north than other diplodocids from the Morrison Formation, so it’s possible they moved south over time
• Had a long whiplash tail, a long neck, an elongated head, and peg teeth (but there are subtle differences in the skull and vertebrae, like a U-shaped notch between the frontal bones)
• Skull looks like a juvenile diplodocid (large eye openings and a rounded snout)
• Had large teeth, and looked like it was smiling
• Probably used gastroliths to help digest
• Described in 2012 by Emanuel Tschopp and Octávio Mateus
• Barnum Brown (known as Mr. Bones) led a team from the AMNH in 1934 on Barker Howe’s land in near Shell, Wyoming. In 6 months they found about 4,000 fossils in an area of 45 x 65 ft (14 x 20 m). Brown said the site was “an absolute, knockout dinosaur treasure trove!” Brown had heard about the site in 1932 from a local collector who had found some large sauropod leg bones that were partially exposed.
• The expedition was funded by Sinclair Oil, and the finds from the trip became Sinclair’s logo (the green sauropod)
• Brown decided to study the fossils on location to figure out the relationships between individuas. Roland Bird suggested they make a quarry chart and draw a map to show where each bone was found
• In the quarry they also found more sauropods (and the first preserved skin tissues of sauropods), as well as ornithischians and Allosaurus. Seemed that there was a group of sauropods being stalked by carnivores and they ran into a watering hole that was a muddy death trap
• After 2 months of making the map, they packed the bones into 140 cases and shipped them back to the museum (weighed 69,000 pounds). However, not many of the fossils were prepared or put on display. Many of the fossils were destroyed in a warehouse fire in 1940, the WWII happened. Brown never made it back to the quarry or got to study the bones
• In 1989 Hans-Jakob Siber, founder of the Swiss Aathal Dinosaur Museum, reopened the Howe Quarry and found more bones, including some neck vertebrae and a partial skull of a sauropod, at first thought to be Barosaurus or Diplodocus
• In 2012 Tschopp and Mateus looked at the bones that were left from the quarry and at AMNH. Tschopp said that “Howe Quarry is the reason I became a paleontologist.” (He’s still working on the collection from the quarry, and identifying bones based on Bird’s quarry map)
• They named specimen SMA 0004 Kaatedocus siberi (in 2013 Schmitt and others referred another partial skull from the Howe Quarry to Kaatedocus)
• Specimen includes a skull and cervical vertebrae
• Type species is Kaatedocus siberi
• Name “Kaate” means small in the Crow (Absaroka) language (one of the tribes in northern Wyoming). The word “docus” alludes to Diplodocus and the Greek word “beam”
• The species name “siberi” is in honor of Hans-Jakob “Kirby” Siber, who organized and funded the excavation, preparation, and curation of the Kaatedocus holotype
• The SMA 0004 is the only specimen from Howe Quarry to be described and properly identified, so far. Need more analysis to better understand diplodocid phylogony and faunal changes in the Morrison Formation
• Tschopp and Mateus said they believed the specimen was a subadult because of its small size and the skull features
• They also said Kaatedocus “is an example of Cope’s Rule, which predicts body size increase during evolution”
• Other dinosaurs that lived around the same time and place include Barosaurus, Stegosaurus, Allosaurus
• Can see Kaatedocus in the sauropods exhibit on the 4th floor of the AMNH, and fossils casts are part of the juvenile sauropod in the Theodore Roosevelt Rotunda

Fun Fact: A few dromaeosaurs are the same size (weight) as modern raptors. Microraptor is about the same size as the peregrine falcon. Velociraptor & Dromaeosaurus are the same size as the Andean condor.