Episode 60 is all about Eoraptor, one of the earliest known dinosaurs of all time.
If you’d like to contribute to our free weekly podcast, then please visit our Patreon page at:
https://www.patreon.com/iknowdino
Thank you so much to our current Patreon supporters. Your generosity helps to keep us going, both emotionally and financially, and we love hearing everyone’s dinosaur requests!
You can listen to our free podcast, with all our episodes, on iTunes at:
https://itunes.apple.com/us/podcast/i-know-dino/id960976813?mt=2
In addition to Eoraptor, we had another great discussion with Brad Jost, host of the Jurassic Park Podcast, a show that covers everything about Jurassic Park and Jurassic World. You can follow Jurassic Park Podcast on Twitter @JurassicParkPod, and listen to our previous cross-over episode in “Styracosaurus: Episode 42.”
In this episode, we discuss:
- The dinosaur of the day: Eoraptor
- Name means “dawn plunderer”
- Named “dawn” because it’s one of the earliest dinosaurs
- Name raptor refers to its grasping hand
- Not related to Velociraptor or dromaeosaurs (other than having raptor in its name)
- Species is Eoraptor lunensis
- Species name means “moon inhabitant” and named based on it being found in the “Valle de la Luna” which looks like a lunar landscape
- One of the earliest dinosaurs (lived in the Triassic, in western Gondwana, now Argentina)
- First described in 1993, and then thought to be the earliest known dinosaur
- Considered an early dinosaur because of its more primitive features
- In 2013, a new dinosaur was formally described: Nyasasaurus from Tanzania, that is believed to be 12 million years older than Eoraptor
- Eoraptor bones were first found in 1991, by Ricardo Martinez, a paleontologist from the University of San Juan (found in Argentina); took 12 months to collect the holotype, then it was prepared at the Field Museum of Natural History in Chicago; it was first put on display in Chicago, and then sent back to San Juan Argentina, where it went on display at the Museum of Natural Sciences
- Paul Sereno and Alfretto Monetta from the National University of San Juan led a team to search for fossils in Argentina in 1991. They searched 5 weeks without finding anything, and then Ricardo Martinez found an Eoraptor tooth (ended up also being a skull and mostly complete skeleton)
- Paul Sereno and colleagues (Forster, Rogers, and Monetta) named Eoraptor in 1993; debate over whether it’s a basal saurischian and a basal theropod
- When first described, thought to be a theropod, based on its hand and other features
- In 1997 Phil Currie said it was closer to a saurischian and ornithischian, and in 2011 a different team found it to be a basal sauropodomorph
- In 2013 Sereno and others redescribed Eoraptor and said it was a basal sauropodomorph
- What changed?
- Originally considered to be a theropod (bipedal, narrow build)
- Another dinosaur that lived in the area was Eodromaeus, which was discovered in 2011, and convinced scientists that Eoraptor was a sauropodomorph, with some teeth suited for eating plants (Eodromaeus had sharp teeth and is considered to be a theropod, and the earliest theropod, which means that Eoraptor, which is more ambiguous, was probably not a theropod)
- Eoraptor and Eodromaeus lived at the same time, which shows one was carnivorous theropod and other was basal sauropodomorph
- Eoraptor and Eodromaeus looked similar and were similar in size
- Early dinosaurs looked similar (though eventually developed into sauropods, theropods, and ornithischians such as stegosaurs, ankylosaurs, and ceratopsians)
- Sereno said “What can I say, I was young,” about mistaking Eoraptor for a theropod. He also said “that if you were transported back 230 million years, and you turned your head as they ran by, you would be really hard-pressed to tell them apart. The differences at the root of the dinosaur family tree are really subtle.”
- Eoraptor was small, at 3.3 ft (1 m) long
- Light, ground-dwelling, bipedal
- Weighed about 22 pounds (10 kg)
- Fast runner
- Probably not the apex predator of its habitat (lived with many archosaurs)
- Herrerasaurus may have eaten Eoraptor (lots of Herrerasaurus bones found)
- Has a kink in its upper jaw
- May have been omnivorous
- Some of its teeth were leaf shaped
- Some of its teeth were curved and saw-edged, but it did not have a sliding joint in its lower jaw to hold large prey in its mouth
- Had five digits on each hand, and the three longest digits on each hand had large claws (probably for prey); the fourth and fifth digits were too small to be used for hunting
- Could also use claws and teeth to tear apart prey
- May have eaten insects and lizards
- Later dinosaurs tended to have fewer fingers (T-rex only had two)
- Forelimbs were half the length of hindlimbs
- Had really large eye sockets, so some scientists think the bones found were of juveniles (also some have skull bones not fully fused together)
- Lived in a volcanically active floodplain with forests; warm and humid, with strong seasonal rain
- Can see Eoraptor in the documentary, Dinosaur Revolution, where an Eoraptor saves a female Eoraptor from a Saurosuchus
- Fun fact: A friend of ours gave us their copy of “Cinefex” from August 1993 which goes into a lot of depth on the creation of the dinosaurs for Jurassic Park. In it they say: “To demonstrate his interest in the project, character creator Stan Winston provided Spielberg’s Amblin Entertainment with detailed pencil drawings of the dinosaurs by Mark ‘Crash’ McCreery. Using ostrich photographs as reference, McCreery sketches the similarly configured gallimimus… …(and) a Tyrannosaurus rex. The T-rex—and all dinosaurs— were to be presented as warm-blooded, agile and fast-moving creatures, a reflection of the latest scientific evidence” and Sam Winston Studio eventually was selected as the effects provider for the full-scale dinosaurs
For those who may prefer reading, see below for the full transcript of our chat with Brad Jost:Continue Reading …