Episode 388: The biggest megaraptorid ever?

Episode 388: The biggest megaraptorid ever?. Maip macrothorax was an enormous megaraptorid and a not-too-distant relative of Tyrannosaurus. It additionally had an impressively cumbersome physique to go together with its presumably fearsome claws.

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  • A brand new huge megaraptorid, Maip macrothorax, was described from Patagonia supply
  • A brand new ornithomimosaur (not but named) has been discovered within the Erlian Formation of Nei Mongol, north China supply
  • The College of Colorado Boulder is returning their Triceratops cranium to the Smithsonian Establishment supply
  • The sport Parkasaurus is now obtainable on Nintendo Swap supply
  • Colin Trevorrow shared a map of Jurassic World: Dominion that confirmed the place the dinosaurs have ended up across the U.S. supply
  • Jurassic World: Dominion dropped a second trailer supply
  • Tom Holtz shared a flowchart to assist decide if you happen to’ve discovered a coprolite, regurgitalite, or different dinosaur meal supply



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The dinosaur of the day: Anchiornis

  • Paravian dinosaur that lived within the Late Jurassic in what’s now Liaoning, China (Tiaojishan Formation)
  • Seems to be rather a lot like a hen, however with feathers on its legs, and enamel, and sometimes depicted as having plenty of feathers on its head (nearly like a crest)
  • In Jurassic World: Camp Cretaceous, Darius Bowman talked about Anchiornis as a doable new dinosaur in Jurassic World, that was introduced whereas he was visiting his father in a hospital
  • Considerably much like trendy birds
  • Closest relative of Aves
  • Anchiornis is about 5 to 10 million years older than Archaeopteryx
  • Small, with 4 wings
  • In regards to the dimension of a crow or pigeon
  • Initially estimated to be 13 in (34 cm) lengthy
  • Holotype estimated to be 34 cm lengthy “reinforces the deduction that small dimension developed early within the historical past of birds,” based on the unique paper
  • Some specimens bigger, so might be as much as 16 in (40 cm) lengthy and weigh 0.55 lb (0.25 kg)
  • Estimated to weigh about 0.24 lb (110 g)
  • Bipedal, with a triangular cranium
  • Had small, unserrated enamel
  • Had a slender, brief scapula
  • Had lengthy arms, lengthy legs, and an extended, bony tail
  • Forelimbs had been about 80% the size of the hindlimbs
  • Had an elongate hindlimb
  • Had lengthy legs, however could not have been a robust runner (runners have a tendency to not have plenty of hair or feathers on legs)
  • Had 4 toes on every foot, and the third and fourth toes had been the longest
  • First toe (hallux) was not reversed, the best way it’s in animals that perch (most likely didn’t perch)
  • Pores and skin and muscle tissue have been discovered
  • Sort and solely species is Anchiornis huxleyi
  • Described by Xu Xing and others in 2009
  • Genus title means “close to hen”
  • Species title refers to Thomas Huxley, “who pioneered analysis into avian origins”
  • Huxley was one of many first to recommend a connection between birds and dinosaurs
  • Sort specimen is articulated, lacking the cranium, a part of the tail, and proper forelimb
  • Holotype consists of articulated skeleton (no cranium), cervical vertebrae, posterior caudal vertebrae, and “faint feather impressions preserved on the slab and counter slab”
  • Holotype might be a sub-adult or younger grownup “full fusion of all of the post-cervical vertebral neurocentral sutures”
  • No LAGs
  • Second specimen discovered was bigger and extra full, with lengthy wing feathers on the palms, arms, legs, and toes
  • A whole lot of specimens have been discovered
  • Shandong Tianyu Museum of Nature in Pingyi County, China, reportedly has 255 Anchiornis specimens of their collections, as of 2010
  • Coated in feathers, with some scales
  • Had lengthy, slender vaned feathers on the wings, legs, and tail
  • Had two forms of downy feathers on the remainder of its physique
  • Had lengthy feathers on the pinnacle which will have fashioned a crest
  • Wing span as much as 20 in (50 cm)
  • Wing had 11 major feathers and 10 secondary feathers, and fashioned a rounded wing
  • Wing feathers had been symmetrical, so not nice for flying
  • Longest wing feathers had been close to the wrist, so the wing was broadest within the center and tapered close to the tip (appeared extra rounded)
  • Had a flap of pores and skin that related the wrist to the shoulder (propatagium), coated in feathers that coated the gaps between the first and secondary feathers
  • Feathers not organized in tracts or rows (not like trendy birds)
  • Had covert feathers that coated many of the wing’s floor
  • Had lengthy, vaned feathers on the hind legs
  • Hindwings had 12 to 13 flight feathers on the decrease leg and 10 to 11 on the higher foot
  • Hindwing feathers had been the longest closest to the physique
  • Made it appear like a four-winged dinosaur (much like Microraptor and Sapeornis)
  • Toes, apart from the claws, had been coated in feathers
  • Foot feathers had been brief and pointed downward
  • A 2010 examine checked out melanosomes in Anchiornis feathers and in contrast them to trendy birds
  • Discovered nearly all of its coloration (besides the tail, which was lacking)
  • First dinosaur the place we knew its coloration was Sinosauropteryx (had a banded orange and white tail)
  • Two most important forms of melanosomes: eumelanosomes (black-grey shades, are usually lengthy and sausage-shaped) and phaeomelanosomes (reddish to yellowish, are usually rounder and jelly bean formed)
  • Assist to determine the colours in dinosaurs
  • Research confirmed that Anchiornis had a feathered crest on the pinnacle
  • Many of the physique was grey and black, crown feathers had been reddish-brown with a grey base, and the face had reddish-brown speckles amongst principally black feathers. Wing feathers had been white with black ideas, and covert feathers had been grey. Bigger coverts on the wing had been additionally white with grey or black ideas, to kind rows of darker dots on the mid-wing (appeared like stripes of even rows of dots on the outer wing, and uneven speckles on the inside wing)
  • Legs had been principally grey, and toes and toes had been black
  • A 2015 examine of a distinct Anchiornis specimen discovered solely gray-black melanosomes, with none reddish coloration within the crown
  • Potential that melanosomes had been preserved in a different way or there have been completely different investigative strategies used, or the primary specimen was smaller, and it might be the reddish-brown coloration obtained changed as Anchiornis grew older. Or might be on account of regional variations or they had been completely different species of Anchiornis
  • In 2010, Quanguo Li and others appeared on the melanosomes of Anchiornis feathers, and recommended the feathers had been for locating mates or different communication (protection postures, startling predators, sending warning indicators)
  • In 2015, Johan Lindgren and others appeared on the molecular construction of feathers in an Anchiornis specimen, and located “unequivocally […] that melanosomes might be preserved in fossil feathers” (some debate earlier than about them being indistinguishable from microbes in pores and skin tissue that colonize throughout decay)
  • In 2012, Nicholas Longrich and others analyzed wing feather association in Archaeopteryx and Anchiornis, and located that they had a number of rows of feathers
  • Discovered that Enantiornithes had trendy wings (oldest one, Protopteryx, from 131 million years in the past, which is about 25 million years after Anchiornis, so could imply that the wing feather association in trendy birds developed over tens of thousands and thousands of years after which stayed principally the identical for greater than 130 million years)
  • Feather association packed collectively layers of comparatively weak feathers, which can have made them robust sufficient to work like airfoils (produces elevate and drag when moved by way of the air), which might have been thicker than these in trendy birds, growing drag at low speeds and lowering drag at larger speeds
  • Overlapping feathers would make it troublesome to take off from the bottom
  • In 2017, Evan Saitta and others discovered Anchiornis to have a “‘shaggy,’ open-vaned, bifurcated feather with lengthy [flexible] barbs connected to a brief rachis”, most likely used for thermoregulation and repelling water, and mixed with open-vaned wing feathers “would have decreased aerodynamic effectivity”
  • Seemed fluffy
  • In 2019, Yanhong Pan and others, analyzed Anchiornis feathers and located alpha-keratins (often solely present in trendy feathers) and beta-keratins, modified in a approach that makes the feathers extra versatile
  • Analyzed feathers from Anchiornis and in comparison with different fossil feathers and trendy flight feathers (from a hen, goose, duck, emu)
  • Discovered trendy birds had principally beta keratins in mature feathers, whereas Anchiornis had beta-keratins and alpha-keratins in its feathers
  • Additional confirmed that feathers could have at first developed for causes apart from flight
  • Signifies that this modification occurred sooner than beforehand thought. Flight feathers had been thought to evolve about 145 million years in the past, and lived about 160 million years in the past, so Anchiornis feathers helps present how feathers developed for flight
  • Initially thought Anchiornis might fly or glide, however later discovered the wings had been too brief
  • A 2016 examine discovered juvenile Anchiornis could have been in a position to make use of wings to assist run up hills, and possibly might fly whereas flapping if utilizing a excessive angle flapping wing stroke, however adults would have been too heavy to fly
  • Flapping whereas operating would have sped it up about 10%
  • Flapping whereas leaping would improve the peak and distance by round 15% to twenty%
  • In 2009, Xu Xing and others described Anchiornis, and wrote “some wrist options indicative of excessive mobility, presaging the wing-folding mechanisms seen in additional derived birds and suggesting fast evolution of the carpus”
  • Additionally mentioned Anchiornis “represents a transitional step towards the avian situation”
  • Had a extra avian-like wrist than different non-avian theropods
  • Avian wrist is modified for wing folding and flying
  • Xiaoting Zheng and others in 2014 analyzed 226 Anchiornis specimens and 96 Sapeornis specimens and located no sternum in both
  • Could don’t have any sternum, which “might signify the plesiomorphic avian situation”
  • Ossified sternum typically lacking in fossil birds. Not having a sternum “recommend that flight capabilities could be severely restricted in basal birds”
  • Present in Anchiornis and Sapeornis, the absence of sternal components are “a real characteristic of those taxa and never an artifact of preservation or ontogeny”
  • Used histology, discovered all of the specimens to be mature
  • Potential the gastralia could have supported the muscle tissues wanted for gliding (if it glided), however it’s unclear
  • A 2010 examine by Alexander and others discovered Anchiornis to be a glider
  • In 2014 Garnet Fraiser recommended the lengthy legs of Anchiornis might be associated to “dorsal using parasitic habits” (using on the backs of different animals), and used for “operating, leaping and climbing over plates and spikes. The necessity for a gliding dismount would clarify lengthy feathers on these lengthy legs”
  • Had massive claws on the third digit of its toes, along with the sickle-shaped second claws
  • Foot pads coated in small, pebble-like scales
  • Had scales on the highest of the toes
  • Some Anchiornis had scales on the toes, tarsus, and decrease leg, so possibly had scales beneath the feathers
  • Had three clawed fingers, the place the longest two fingers had been caught along with pores and skin and tissue from the wing (so mainly solely had two fingers)
  • Pores and skin across the backside of the fingers and the toes had been coated in tiny, rounded scales
  • In 2018, Xiaoting Zheng and others studied six gastric pellets attributed to Anchiornis, which had “frivolously acid-etched lizard bones or fish scales”
  • Made Anchiornis the earliest, most basal identified theropod identified to supply gastric pellets
  • Solely definitively identified gastric pellets from any non-avialan theropod
  • Pellets had been much like these of contemporary birds
  • Pellets are undigested components meals which might be regurgitated
  • Helps present a digestive system much like trendy birds, “and that the evolution of contemporary avian digestion could have been associated to the looks of aerial locomotion on this lineage” (birds have a excessive metabolism)
  • Anchiornis had a two-chambered abdomen, environment friendly antiperistalsis (propels meals from the abdomen again as much as the mouth), low abdomen acidity, and brief gastric residence, which can imply this specialised digestive system, additionally seen in birds, was ancestral in Paraves and even Maniraptora
  • Regurgitating would have improved Paraves’ digestion effectivity, which can have helped give it power for aerial locomotion, and early paravians might even have shortly gotten rid of any non-digested meals, to make themselves lighter shortly
  • Anchiornis was most likely an opportunistic generalist hunter
  • Presence of three lizard skeletons present in one pellet
  • Fish could have been an enormous a part of its weight loss plan, primarily based on 5 of the six pellets containing solely fish scales
  • Anchiornis didn’t appear nice for catching fish. In comparison with birds that reside close to water, it had plenty of feathers under the knee, and it had a comparatively brief snout (often birds that catch fish have lengthy, slender payments)
  • Fish discovered might imply Anchiornis might catch some fish, or there’s a preservation bias for the fish-bearing pellets and it doesn’t present its true weight loss plan
  • Lived in a subtropical to temperate local weather, that was heat and humid
  • Different dinosaurs that lived across the identical time and place embrace different bird-like dinosaurs Aurornis, Eosinopteryx, Scansoriopteryx, Serikornis, and Xiaotingia, and the heterodontosaur Tianyulong
  • Different animals that lived across the identical time and place included pterosaurs, salamanders, bugs, arachnids, and mammals

Enjoyable Reality:

Except for Anchiornis, few fossilized gastric pellets have been discovered with non-avian dinosaurs.

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