Episode 348 is all about Orodromeus, a small quick ornithopod identified from a progress sequence at Egg Mountain.
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On this episode, we focus on:
Information:
- A redescription of Scutellosaurus reveals that it was bipedal supply
- “Megaripples” discovered a mile beneath Louisiana had been brought on by a tsunami after the impression that worn out the dinosaurs supply
- The Kuji Amber Museum in Japan has a show of lately found fossilized enamel from three theropod species supply
- There’s a time-lapse video of all 292 bones of Dippy getting assembled at Norwich Cathedral supply
- Warren Elsmore additionally in Norwich has a Jurassic Lego exhibition till Aug 30 together with 500,000 Lego blocks and components supply
- Whipsnade Zoo in Bedfordshire, England has a brand new Zooasic Park till Sept 5 supply
- A “Information to vaccination for dinosaurs” was posted in Malaysia after somebody received there COVID vaccine in an inflatable T. rex costume supply
- Google Chrome’s Dinosaur recreation has been up to date to incorporate Olympic occasions supply
The dinosaur of the day: Orodromeus
- Ornithopod that lived within the Late Cretaceous in what’s now Montana, US (Two Drugs Formation)
- Seems like different ornithopods, with a small head, lengthy physique and tail, and lengthy legs
- Estimated to be 8.2 ft (2.5 m) lengthy
- Bipedal and small, however quick
- Extraordinarily gracile and a quick runner, based mostly on hindlimb proportions
- Discovered on the Egg Mountain website (identical as Maiasaura)
- Described in 1988 by Jack Horner and David Weishampel
- Jack and Horner and David Weishampel described embryonic dinosaur stays in 1988
- “We report right here the primary well-documented affiliation of dinosaur eggs containing embryos, juveniles and adults from the fossil document”
- Kind species is Orodromeus makelai
- Genus identify means “Mountain Runner”
- Genus identify alludes to “Egg Mountain” in addition to the state of Montana, and to the animals, presumed cursorial habits
- Species identify is in honor of “the late Robert Makela for his many dinosaur discoveries together with the holotype”
- Holotype is an almost full juvenile skeleton with out arms and tail
- Referred materials consists of the clutch of 19 eggs with embryos, hind legs, a pair skeletons, one other cranium, and a braincase (6 people plus the clutch)
- One particular person is about 60% full and smaller, and doubtless a near-hatchling
- One other is extra mature, and has a crushed cranium
- One other can also be mature, pretty full disarticulated skeleton
- Discovered a clutch of 19 unhatched eggs with embryonic skeletons, discovered with eggshell fragments from different nests containing younger Maiasaura
- Stated Orodromeus was precocial after hatching (fairly energetic proper after hatching), after evaluating nesting patterns and bone histology with Maiasaura
- Enamel from the Judith River Formation, initially referred to Thescelosaurus, was referred to Orodromeus by Galton in 1995
- One specimen and eggs from Egg Mountain are actually thought-about to be a troodontid, presumably Stenonychosaurus
- Horner and Weishampel in 1996 thought they had been Troodon (revealed a correction in a letter to Nature, and stated “additional preparation of the embryo has revealed the identification to be that of the theropod dinosaur Troodon formosus” (based mostly on the enamel), then in 1997 Varricchio and others described a partial grownup Troodon skeleton with a clutch of not less than 5 eggs, in all probability in a brooding place
- Van der Reest and Currie stated it was potential that troodontid was Stenonychosaurus
- Rodney Scheetz wrote a thesis (unpublished?) on the osteology of Orodromeus in 1999
- Based on Scheetz, an alternate cause for thus many younger Orodromeus carcasses in Troodon nesting space could also be as a result of Troodon adults introduced them in as prey for his or her younger (would assume there have been extra hind-limb components, “because the hind-quarters of the animal would represent the most important meat mass” (Scheetz’s evaluation discovered that to be true)
- Nonetheless numerous Orodromeus discovered. Scheetz’s thesis stated he described materials of 99 different specimens
- Second species is Orodromeus minimus (presumably Laosaurus minimus)
- Charles Gilmore described Laosaurus minimus in 1909 based mostly on a partial left hindlimb and items of vertebra present in Alberta, Canada (Allison Formation)
- In 1949 Loris Russell discovered it to be most like Hypsilophodon, based mostly on the locality the place the fossils had been found having been discovered within the early Nineteen Thirties to be the Stomach River Group as an alternative of the Blairmore Group
- Within the Eighties, Galton prompt it was Troodon, based mostly on unpublished proof
- In 1990, Sues and Norman discovered Laosaurus minimus to presumably be Orodromeus minimus, however there weren’t sufficient fossils to make sure
- Horner and Weishampel stated, “Tooth put on signifies reversion to (or retention of) the primitive high-angle, fabrosaur-like type of chewing”
- Household Fabrosauridae now thought-about to be basal Ornithischia
- Primarily based on a 2013 examine by Jordan Mallon and others, a small ornithopod like Orodromeus in all probability ate meals that was at most about 3 ft (1 m) excessive
- Scheetz stated the triangular enamel with the excessive angle of how the enamel match collectively could present a shift to consuming bugs
- Attainable the enamel had been that manner in infants, after which the identified Orodromeus specimens had been younger, or the adults stored that “neonate situation” whilst they grew
- Had boss-like growths on its cheek bones
- Zephyrosaurus could also be carefully associated to Orodromeus, based mostly on each having bosses on their cheeks (talked about in episode 306)
- Could have burrowed, like Oryctodromeus, based mostly on how the fossils had been discovered packed collectively in locations that they often would have been discovered scattered (however no clear proof)
- Jack Horner and others in 2009 in contrast histology and progress of Orodromeus, Dryosaurus, and Tenontosaurus
- Checked out perinate (embryos or lately hatched), juveniles, sub-adults, and adults
- Typical perinate had a femur size of (0.6 in) 16 mm
- Had smaller and bigger juveniles
- Sub-adult femur poorly preserved and destroyed by bacterial-mycelial actions
- Grownup tibia additionally invaded by micro organism
- Grownup femurs had been 7-7.8 in (180-200 mm) or higher in size
- Did attain a progress plateau
- Discovered first LAG on the late juveniles, which is analogous to Maiasaura (however Maiasaura is far larger)
- Couldn’t rely the precise variety of LAGs on the grownup (too poorly preserved), however counted not less than 5 within the higher preserved people
- Estimated the late juveniles to be 3 to 4 years previous, and that Orodromeus reached grownup dimension 1 to 2 years after that
- Orodromeus was comparatively small, however nonetheless had appreciable progress trajectory from embryo to grownup
- Grew rapidly after hatching, then slowed down as a later juvenile
- Most likely grew quicker than a crocodile however not as quick as a chook
Enjoyable Truth:
Ankylosaurs (& different dinosaurs) might have floated for weeks earlier than lastly sinking and fossilizing.
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