Episode 55 is all about Elaphrosaurus, a small theropod whose name means “light weight lizard.”
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In this episode, we discuss:
- The dinosaur of the day: Elaphrosaurus
- Name means “light weight lizard”
- Ceratosaur theropod, also in the Averostra group
- Lived in Jurassic in Tanzania, Africa
- Described and named by Werner Janensch in 1920
- Type species is Elaphrosaurus bambergi
- Mostly known from one nearly complete skeleton (no skull)
- Type specimen Elaphrosaurus bambergi was found in 1910 by Werner Janensch, I. Salim, H. Reck, and Parkinson (now in the Humboldt Museum in Berlin, Germany)
- First classified as a coelurid (wastebasket taxon for small theropods at the time). Put in the Ornithomimidae family in 1928 by Nopcsa due to light frame. Limbs look similar to Coelophysis, and in 1990 Barsbold, Maryanska and Osmolska classified it as ornithomimid. Carrano and Sampson in 2008 and Carrano et. al in 2012 study assigned it to the genus Ceratosauria (Limusaurus it now considered to be the closest relative)
- Some fossils found over the years thought to be Elaphrosaurus, but now considered dubious.
- Includes Elaphrosaurus iguidiensis (described by Lapparent in 1960), with fossils collected from Algeria, Libya, and Niger (more than 40 teeth, caudal vertebrae, and a complete tibia), but came from three different localities and are not the same species
- Also Elaphrosaurus gautieri (described by Lapparent in 1960), found in Niger and consisted of a complete neck vertebrae, but now renamed Spinostopheus gautieri by Sereon et. al in 2004
Elaphrosaurus philtippettensis (named in 1995 after Phil Tippett, visual effects supervisor who worked on Jurassic Park) has a tibia, humerus, some metatarsals, but Carpenter et al. in 2005 said they were probably not certosaurian and more likely Tanycolagreus (coelurid theropod)
- Elaphrosaurus agilis, described in 1972 by Dale Russel (based on pubic bones Charles Marsh had named Coelurus agilis, which he thought was a larger version of the type species Coelurus fragilis.
- But in 1980 John Ostrom confirmed Charles Gilmore’s notion that C. agilis was synonymous with C. fragilis, so Elaphrosaurus agilis is the same as C. fragilis
- Elaphorsaurus was medium sized (up to 20 ft, 6.2 m long) and bipedal
- 5 ft (1.46 m) at hip, weighed about 463 lbs (210 kg)
- Long, thin neck, and stiff tail
- Long trunk, but shallow chest (compared to other theropods similarly sized)
- Short hindlimbs (legs), compared to its long trunk
- Tibia (shin bone) longer than femur (thigh bone), so probably a fast runner
- 3 toed feet
- Short, thin arms with 3 fingers on hands
- Dinosaurs in the same time and place: sauropods Giraffatitan, Australodocus, Tornieria and Dicraeosaurus, theropods, carcharodontosaurid Veterupristisaurus, stegosaurid Kentrosaurus, iguanodontian Dysalotosaurus. Other animals included pterosaurs and early mammals.
- Elaphrosaurus was too small to hunt sauropods and stegosaurs and probably went after smaller herbivores
- In addition to Africa, Elaphrosaurus may have also been found in the Morrison Formation in the U.S.
- But small theropod fossils in the Morrison Formation are relatively rare (in terms of having not been found yet)
- In 2001, Chure referred to the right tibia of a small theropod in Garden Park, CO as Elaphrosaurus (but there has been debate; in 2008 Carrano and Sampson suggested it was closer to Tendaguru than Elaphrosaurus
- Elaphrosaurus and other dinosaurs found in the Tendaguru were mounted in the museum in Berlin after WWI, even with the economic slump, riots, and strikes. Elaphrosaurus was the second dinosaur mounted (in 1926, after Kentrosaurus in 1924), the third was Dicraeosaurus in 1930-1)
- Averostra (name means “bird snouts) is a clad that includes most theropods that have a promaxillary fenestra (an additional opening in the front of the maxilla)
- Gregory S. Paul named Averostra in 2002, though Martin Excurra and Gilles Curry redefined it in 2007
- Ceratosaurs are theropods with more in common with Ceratosaurus than with birds (no agreed upon listing of characteristics)
- Latest theory is it includes theropods from the late Jurassic to late Cretaceous
- Fun Fact: Richard Owen spent a lot of time researching mammals, and in 1834, the London Zoological Society purchased a male Indian Rhinoceros, at his request. Then 15 years later when the rhinoceros died, he apparently brought it home to dissect it, and his wife discovered it in their front hall when she got home.