I Know Dino Podcast Present Notes: Ornitholestes (Episode 80)

Episode 80 is all about Ornitholestes, a carnivorous theropod with a small head.

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On this episode, we focus on:

First theropod found within the 1900s
Holotype expedited by Peter Kaisen, Paul Miller, and Frederic Brewster Loomis
Identified from one partial skeleton with a crushed cranium (discovered on the Bone Cabin Quarry in Wyoming, close to Drugs Bow, in 1900)

Partial skeleton contains components of the vertebral column, forelimbs, pelvis, and hindlimbs
Later, there was an incomplete hand considered Ornitholestes, however is taken into account Tanycolagreus
Tanycolagreus was discovered just a few hundred yards from Ornitholestes (that’s why the hand was assigned to it, at first)

Sort species (solely species) is Ornitholestes hermanni
Named after the American Museum of Pure Historical past preparator Adam Hermann (directed the restoration and mounting of the skeleton)
Theodore Gill urged the genus title

Charles Gilmore stated Ornitholestes was an identical to Coelurus (1920), and in 1934 Oliver Perry Hay stated there was solely a distinction on the species degree, and renamed Ornitholestes, Coelurus hermanni; in 1980 John Ostrom revived the genus Ornitholestes
Bipedal carnivore
Had a head proportionally smaller than most different carnivorous dinosaurs

Had a brief snout and strong decrease jaw
Had conical entrance tooth, again tooth have been recurved and serrated (Henry Osborn stated there have been 4 tooth within the premaxilla, Gregory S. Paul in 1988 stated the cranium had solely three remaining premaxillary tooth)
Had giant eye sockets, that have been greater than 25% of the cranium’s size

Massive eyes might have been used to hunt at evening
Small cranium means it might have been troublesome to catch prey with its mouth (most likely used arms)
Had robust arms

Might tuck fingers near physique, much like the way in which a fowl holds its wing
In 2006 Phil Senter did a biomechanical examine utilizing Ornitholestes casts (the proper forelimb) to determine its vary of movement (discovered it might swing in a 95 diploma vary, and will bend its elbow at a 53 diploma angle, which is extra acute than Maniraptoriformes (can bend forearms to 90 levels), however absent in primitive theropods like Coelophysis and Allosaurus
Forearm couldn’t kind a straight angle, so the forearm was completely rotated upward

Could have used its forearms to know prey (with each fingers)
Osborn described Ornitholestes as having “speedy greedy energy” of fingers, “balancing energy” of tail, and enormous, conical entrance tooth (he noticed as adaptation to prey on up to date birds); then in 1917 Osborn urged Ornitholestes was an early transition from carnivore to herbivore, however Charles Knight drew Ornitholestes chasing Archaeopteryx (and different illustrations like this have continued to look)
Ornitholestes got here from western U.S., Archaeopteryx identified from central Europe

Could have eaten birds, fish, small vertebrates, mammals, lizards, frogs, salamanders, hatchling dinosaurs, or gone after different small theropods (if it hunted in packs, might have been capable of prey on juvenile Camptosaurus)
In all probability ate about 1.5 lb or 700 grams of meals a day
Could have been prey for bigger theropods (Ceratosaurus and Allosaurus)

Had a brief, S-shaped neck and a protracted, whiplike tail (over half the size of its physique)
Had lengthy forelimbs, about 2/3 the size of its hind legs
Had pretty quick hind legs; Osborn calculated that the shin bone was solely 70% so long as the thigh bone (shin bone was lacking)

Considered a quick runner, however decrease leg bones considered shorter than the femur (so most likely didn’t chase after different small dinosaurs)
In 1969 John Ostrom stated that the innermost toe (digit II) was bigger than digits III and IV, and that digit II might have had a modified sickle claw, like Deinonychus (however digit II is in poor situation so it’s onerous to know for certain)
Depicted as having a small crest on its snout (considered for show), however now thought there was no crest

Has a damaged bone close to the nostril that appears to bulge upward, which made Gregory S. Paul suppose it had a nasal horn “somewhat like a hen’s comb in appears to be like” in response to his Predatory Dinosaurs of the World in 1988; however in 2003 Oliver W.M. Rauhut and in 2005 Kenneth Carpenter stated it didn’t have a nasal horn however that the bulge was from the cranium being crushed after the dinosaur died
Percy Lowe stated in 1944 Ornitholestes might have had feathers
Due to Sinosauropteryx (primitive coelurosaur present in 1996) had furlike feathers, most paleontologists suppose all coelurosaurs most likely had some sort of insulating feathers; John Foster in 2007 stated Ornitholestes most likely had extra primitive feathers than birds, used for insulation and presumably brooding eggs, and would have lined a lot of the physique

If Ornitholestes had feathers used for insulation, most likely had a quick metabolism and was fairly lively
Due to its dimension, Ornitholestes was thought of a coelurosaur, however in 1986 Jacques Gauthier redefined Coelurosauria
Friedrich von Huene named the infraorder Coelurosauria in 1914 (for some time it was a taxon wastebasket for small theropods)

However in 1986 Jacques Gauthier redefined Coelurosauria
In 1988 Gregory Paul stated Ornitholestes had an analogous cranium to Proceratosaurus (Center Jurassic theropod, present in England), and he put the 2 collectively in Ornitholestinae, a subfamily of Allosauridae; however Proceratosaurus is a tyrannosaur so this classification is untenable
Now Ornitholestes thought of Coelurosauria, as outlined by Gauthier (some suppose it’s essentially the most primitive member of Maniraptora)

Coelurosauria group is considered nearer to birds than extra primitive theropods, similar to Allosaurus
Coelurosauria means “hole tailed lizards”
Clade contains theropods extra intently associated to birds than carnosaurs

Coelurosaurs have a sacrum (vertebrae that attaches to the hips) longer than in different dinosaurs, a tail that stiffens in the direction of the tip, a bowed decrease arm bone, and a tibia longer than the femur
Enjoyable reality: Fossils are the proper candidates for CT scans. Once a fossil is scanned it’s quite simple to make a 3-D mannequin, after which you may 3D print out as many copies as you need! It’s nonetheless not fairly nearly as good as conventional casting methods due to 3-D printing decision limits, but it surely’s getting higher on a regular basis!

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