Episode 59 is all about Falcarius, one of the earliest theropods to switch from eating meat to eating plants.
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In this episode, we discuss:
- The dinosaur of the day: Falcarius
- Name means “sickle cutter”
- Falcarius is named for its sharp claws
- A therizinosaurian dinosaur that lived in the early Cretaceous in Utah
- Falcarius bones were first found in 1999 by Lawrence Walker (a commercial fossil collector). He told paleontologist James Kirkland, and in 2001 Kirkland and a team from the Utah Geological Survey helped uncover bones in Utah’s Cedar Mountain Formation
- Lawrence Walker sold fossils on the black market, but he thought Falcarius was an important find, so he came forward (and spent five months in jail and paid a $15,000 fine). Kirkland said “He may be the first person to ever go to jail for fossil theft on public land.”
- Two bonebeds were found, of hundred (maybe thousands) of Falcarius individuals (in 2006, estimated there were at least 300 individuals, in 2005, more than 2,000 specimens excavated, many disarticulated bones, also juveniles); in 2010 there were over 2,700 individuals found, by the end of 2010 over 3,000
- A second site was found in 2008 (Suarez Quarry) with many adults, possibly a slightly different type of Falcarius
- Both graveyard sites may have been associated with a spring (reason for so many individuals there), and may have died due to drought, toxic gasses, or bacteria (they all come togehter at those springs, at least periodically)
- Because there are so many individuals of different sizes and ages, it will be great for research and finding out how fast they grew, when they matured, how much variation was between them
- Falcarius was first described in 2004, though it wasn’t formally named until May 2005. Co-authors, including Scott Sampson and Lindsay Zanno (but not Jim Kirkland) said that Falcarius “is the missing link between predatory dinosaurs and the bizarre plant-eating therizinosaurs.”. Lindsay Zanno also said Falcarius is “The ultimate in bizarre: a cross between an ostrich, a gorilla, and Edward Scissorhands.”
- Type species is Falcarius utahensis
- Falcarius helps to show the early evolution of Therizinosauria (its group) and their relationship to other theropods (Falcarius shows a transition between older theropods and Therizinosauridae)
- Falcarius shows the change from a meat eater to a plant eater (some think it was an omnivore)
- Not clear why these dinosaurs switched from eating meat to eating plants (especially since they were adapted to be successful meat eaters)
- Falcarius lived around the time of the first flowering plants in the fossil record (could be a reason to switch)
- Therizinosaurs evolved from raptorlike group of dinosaurs (Maniraptora)
- Falcarius seems to be proof that therizinosaurs evolved from raptor-like dinosaurs, though not directly from Velociraptor, but from a common ancestor not yet known
- In the 1990s Kirkland found the first therizinosaur in North America, Nothronychus, which was younger than the oldest therizinosaurs from Asia (so they originally thought therizinosaurs started in Asia and migrated on the land bridge between Alaska and Siberia to get to North America)
- Falcarius is 125 million years old, as old as the oldest known Asian therizinosaur, Beipaiosaurus, and is more primitive (also, some evidence that the land bridge didn’t exist 125 million years ago)
- Falcarius is the most primitive dinosaur in the therizinosaur group, and shows they probably used to live all over the northern hemisphere
- So, therizinosaurs may have originated in North America and then gone to Europe and Asia (most likely migrated via Europe, some paleontologists think we may someday find a therizinosaur in England)
- Falcarius was an in-between therizinosaurid: had a long neck, small head, and teeth for eating plants, but also had a long tail, propubic pelvis, and long leg and foot with one toe that didn’t touch the ground (like other theropods)
- One of the earliest theropods to eat plants
- Scientists know this because it had a large gut (more proof it digested tough plant matter)
- Wide pelvis to accomodate the larger gut (used to get nutrients from plants)
- Digesting plants is harder than digesting meant (need bigger digestive systems to process plants)
- Before Falcarius, it was very rare to see the transition between meat eaters and plant eaters
- Long neck, so could potentially eat leaves about 5 ft (1.5 m) off the ground
- Teeth good for shredding leaves (similar to modern iguanas)
- Had at least 16 teeth in the maxilla of the upper jaw, and 28 teeth in the lower jaw
- Teeth were leaf-shaped, and maxillary teeth were finely serrated (showed it ate plant material)
- The front five teeth of its lower jaw are longer, straighter, and more pointed (may have been omnivorous–eating small animals such as lizards)
- “Craniocervical Myology and Functional Morphology of the Small-Headed Therizinosaurian Theropods Falcarius utahensis and Nothronychus mckinleyi” by David K. Smith, published Feb 2015
- The study reconstructed craniocervical musculature in Falcarius and Nothronychus based on Tyrannousaurs, Allosaurus, and some extant birds as models
- Knowing this information makes it easier to understand their feeding behavior
- Had a reduced bite force, compared to carnivorous theropods
- May have eaten at a constant level or low grazing
- Probably used its arms a lot for gathering food
- Bipedal herbivore/omnivore
- About 12-13 ft (3.7-4m) long and just over 4 ft (1.2 m) tall
- Gregory S. Paul estimated it weighed about 220 lb (100 kg)
- Smallest juvenile found was about 1.6 ft (0.5 m) long
- Small head and long neck and tail
- And had fairly long arms
- Hand claws that were large, slightly recurved (4-5 in or 10-13cm) long claws, probably used for defense
- Not much known about its head. Small, and elongated
- Had relatively large braincase
- Relatively long leg, so could easily run
- Thigh bones were longer than shin bones (could run fast, adapted for running after prey, compared to later therizinosaurids with long shin bones, and probably waddled around)
- Had three-weight bearing toes in foot (first toe didn’t touch the ground)
- Based on relatives from China, paleontologists think Falcarius had downy feathers
- Can see Falcarius at the Utah Museum of Natural History
- Falcarius is part of Therizinosauridae
- They had wide hips, a pretty large braincase, and long necks
- Asian Therizinosauridae had quill-like feathers
- Most therizinosaurs have been found in Asia
- Only one other therizinosaur found in North America so far: Nothronychus
- For years therizinosaurs were thought to be giant sea turtles, or long-necked sauropods
- Scientists have compared them to giant sloths (big and slow)
- Fun Fact: According to a paper in 2006 in PNAS, Steve Wang and Peter Dodson stated that 527 dinosaur genera had been described to date and estimated that there were about 1300 left to discover. They show a predicted S curve in the article which shows us in the steep increase thus we are in the “golden age.” And according to the “Dinosaur Genera List,” there are currently 1007 well established dinosaur genera. Just for fun: Compare that to the number of (obviously fictional) Pokemon at 721
