Episode 288 is all about Nothronychus, the most complete therizinosaur ever found.
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In this episode, we discuss:
News:
- #BlackBirdersWeek is everywhere this week, spreading images and facts in support of Black nature enthusiasts and birders source
- The South American elaphrosaur Huinculsaurus is the youngest described to date source
- In Taipei, Taiwan, Evolution of the Banana Fish Solo Exhibition is going on until June 6 source
- A set of Jurassic Park gates are for sale after being used for an Australian girl’s birthday source
- Near Darwin, Australia a large fiberglass dinosaur known as Big Kev was recently reassembled source
- The 28th season of Power Rangers will be called Power Rangers Dino Fury source
- Captain Marvel #9 had Captain Marvel take out two T. rex with a single punch source
The dinosaur of the day: Nothronychus
- Therizinosaur theropod that lived in the Cretaceous in what is now North America
- Herbivore, but a theropod
- Weighed about 1 tonne
- Bipedal and walked pretty upright
- Had a small head
- Had a beak, and four toes on each foot (all toes faced forward)
- Had leaf-shaped teeth
- Had a long neck, long arms, and three long claws on each hand
- Also had a “pot-belly”, short, stumpy legs, and a short tail
- Claws were about 9 in (22 cm) long
- Could eat tough plants
- Therizinosaurs may have had primitive feathers
- Type species is Nothronychus mckinleyi
- Described and named in 2001 by James Kirkland and Douglas Wolfe
- Second species named in 2009 by Lindsay Zanno and others: Nothronychus graffami (found in the Tropic Shale of Utah, 1.5 to 3 million years older than Nothronychus mckinleyi
- Nothronyhcus graffami estimated to be 15 to 20 ft (4.5 to 6 m) long (Nothronychus mckinley a little smaller)
- Nothronychus mckinleyi was not as robust as Nothronychus graffami, and its ulna was more bent
- Genus name means “slothful claw”
- Probably used large claws to hook branches and eat in a style similar to a sloth
- Species name is in honor of Bobby McKinley (fossils found on his land)
- Merle Graffam found the second specimen (and species) in Utah in 2000 (a large toe bone)
- First therizinosaurid found in North America (previously found in China and Mongolia)
- Therizinosaurids were herbivores, but many of their relatives were carnivores
- Big belly meant had a large digestive system (good for digesting vegetation)
- Therizinosaurids are thought to be primitive Maniraptors, a group that started in Asia and includes Velociraptor
- Discovery of Nothronychus helped show that dinosaurs like Therizinosaurus (herbivorous theropod) were not as rare as previously thought, and that many kinds of Maniraptorans were herbivores or omnivores, which meant they could travel to new areas and branch out and become a more diverse group
- Possible the Maniraptoran common ancestor was an herbivore or omnivore
- Lindsay Zanno said in a LiveScience article in 2009, that “predatory maniraptoran dinosaurs like Velociraptor must have re-evolved exclusive meat-eating”
- Therizinosaurs had lots of teeth, didn’t replace their teeth that often, long necks and small skulls, and large guts, among other characteristics that show they were herbivores
- When Therizinosaurus, the first therizinosaur, was found, it was originally thought to be a giant sea turtle because of its large claws (later became a therizinosaurid when more fossils were found and referred, including a hindlimb and forelimb)
- Nothronychus mckinleyi was excavated in the early to mid 1990s
- Found in New Mexico, near the border of Arizona, in the Zuni Basin (Moreno Hill Formation, Haystack Butte site, around 91 million years ago)
- First fossil found was a hip bone but was originally thought to be part of the skull crest of the ceratopsian Zuniceratops
- Holotype includes skull fragments, braincase, vertebrae, parts of the shoulder girdle, forelimbs, pelvis, and hindlimbs
- Barry Albright and others excavated Nothronychus graffami in 2000
- Found about 80% of Nothronychus graffami skeleton, but it was pretty crushed
- Also no skull
- Utah find was a surprise because the area was known to be under the Western Interior Seaway in the Late Cretaceous, but most likely was swept out to sea after it died)
- Shoreline/land on the Western Interior Seaway was about 60 mi or 100 km away from where Nothronychus graffami was found
- Nothronychus graffami found in an area with lots of plesiosaurs and other marine fauna
- Nothronychus mckinleyi found in an area that included the ceratopsian Zuniceratops, hadrosauroid Jeyawati, tyrannosaurs, and lots of fossilized wood
- Can see Nothronychus graffami at the Natural History Museum of Utah
Fun Fact: Dinosaur claws, horns, and plates, were all likely covered in keratin, making them much larger than their skeletal mounts make them appear.
