Episode 432: Microraptor’s hawk ft and Allosaurus scavenging

Episode 432: Microraptor’s hawk ft and Allosaurus scavenging. Some dinosaurs had spikes on the underside of their ft, whereas others had additional sturdy toes, the main points inform us about how they lived and hunted. Plus an replace on the Allosaurus scavenger speculation.

Information:

• A critique of the controversial Allosaurus as a scavenger paper supply
• Response by the unique authors on why they nonetheless assume Allosaurus is a scavenger supply
• Microraptor had ft like a contemporary hawk (and what chook ft can inform us about dinosaur habits) supply
• There’s a cool trailer for Talon, a few Dakotaraptor with magical powers supply

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The dinosaur of the day: Duriavenator

• Basal megalosaurid theropod that lived within the Center Jurassic in what’s now England (Oolite Formation)
• Briefly talked about in episode 47, Megalosaurus
• Megalosaurus was a wastebasket taxon (David Norman in 1985 mentioned it was used as a “dustbin”)
• Thought of to be medium-sized
• Estimated to be 16 to 23 ft (5 to 7 m) lengthy and weigh 2,200 lb (1 tonne)
• In all probability appeared just like Megalosaurus, with an elongated head, lengthy tail, and walked on two legs
• As a megalosaurid, in all probability had muscular arms to assist catch and kill prey
• Had distinctive options within the jaw, together with deep grooves
• Vomer (a part of the bone on the center of the palate) was just like Allosaurus
• Had curved, serrated enamel
• Enamel have been completely different from Megalosaurus, together with in the best way the entrance enamel of the decrease jaw slanted ahead
• Had heterodont enamel (completely different enamel), together with enamel on the entrance of the decrease jaw being longer than enamel within the again
• Could have helped pluck and grasp when consuming
• Had alternative enamel seen within the tooth sockets
• Sort species is Duriavenator hesperis
• Genus title means “Dorset hunter”
• Species title means “the West” or “western”
• Fossils present in 1882 in Dorset, close to Sherborne
• Richard Owen described the entrance third of the cranium, together with a part of the higher jaw, the correct maxilla, a part of the bone on the center of the palate (vomer), each dentaries (decrease jaw), and different components of the decrease jaw, and related enamel, in 1883, as Megalosaurus bucklandii
• Fossils are on the Pure Historical past Museum in London
• Fossils discovered by Edward Cleminshaw, when, in keeping with Richard Owen, “blocks of this stone have been in course of preparation for a constructing, when indications of imbedded fossils being detected by Mr. Cleminshaw on fractured surfaces of the quarry-stones, he withdrew all such from the constructing yard and transmitted them to the British Museum for identification”
• The precise spot the place the fossils have been discovered is unclear, although in 1916 Richardson wrote that “The location of the quarry by which the stays have been discovered may be very close to the again of the homes on the north aspect of Chilly Harbour Highway”
• Richard Owen thought the fossils have been Megalosaurus bucklandii
• Megalosaurus bucklandii cranium was solely recognized from fragments
• Owen wrote the variations between the fossils Cleminshaw discovered and Megalosaurus bucklandii have been within the measurement of the jaw, however the enamel have been related in measurement, type, and construction, so “there was no floor for predicating distinction of species”
• Owen additionally thought the big opening behind the maxilla was an eye fixed socket (now recognized to be the opening, or fenestra, in entrance of the attention socket)
• Owen estimated the diameter of the eyeball to be 2 inches
• In 1926, Friedrich von Huene based mostly his cranium reconstruction of Megalosaurus bucklandii on these fossils (the specimen from Dorset)
• He additionally mentioned lots of the fossils assigned to Megalosaurus in all probability weren’t Megalosaurus
• In 1964, Alick Walker discovered that the specimen from Dorset was older than Megalosaurus bucklandii and “no less than particularly distinct from the latter”
• Additionally discovered small variations within the jaws, and variations within the tooth sockets
• In 1974 Michael Waldman redescribed the specimen and renamed it as Megalosaurus hesperis
• Discovered variations within the variety of enamel, and mentioned Megalosaurus hesperis had extra enamel, however that he couldn’t evaluate any additional as a result of there weren’t sufficient fossils
• Additionally discovered that the premaxilla just like Allosaurus, however discovered Megalosaurus hesperis and Allosaurus to be completely different because of the approach the jaws curve and the positions of the tooth carina (pertains to the slicing fringe of the tooth)
• A number of individuals questioned Megalosaurus hesperis. Gregory Paul listed it as Megalosaurus? hesperis, and Thomas Holtz in 2000 referred to it as “Megalosaurus” hesperis, for instance
• Samuel Wells and Jaime Emilio Powell deliberate to rename Megalosaurus hesperis as Walkersaurus, nevertheless it was not printed and the title is taken into account to be nomen nudum
• Holtz and others in 2004 additionally mentioned there was no diagnostic characteristic of Megalosaurus hesperis, although it might nonetheless be its personal species, and Darren Naish and David Martill in 2007 discovered it to be a sound species however in all probability wasn’t Megalosaurus
• In 2008, Roger Benson and others discovered that solely the fragment of the jaw used to call Megalosaurus was positively Megalosaurus bucklandii, although later additionally discovered a number of extra fossils additionally belonged to Megalosaurus bucklandii
• In 2008, Roger Benson redescribed Megalosaurus hesperis and located it to be completely different sufficient to rename as Duriavenator
• Different animals that lived across the identical time and place embrace the megalosaurid Magnosaurus, sauropods, stegosaurs, ornithopods, and marine invertebrates

Enjoyable Reality:

There aren’t any “residing fossil” species which have survived for the reason that Mesozoic.

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