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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 along 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 out there 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 when you’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 rather a lot like a chicken, however with feathers on its legs, and tooth, 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
    • Concerning 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 advanced early within the historical past of birds,” in keeping with the unique paper
    • Some specimens bigger, so may very well 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 tooth
    • Had a slender, quick scapula
    • Had lengthy arms, lengthy legs, and a protracted, bony tail
    • Forelimbs had been about 80% the size of the hindlimbs
    • Had an elongate hindlimb
    • Had lengthy legs, however might not have been a powerful 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 way in which it’s in animals that perch (in all probability 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 identify means “close to chicken”
    • Species identify refers to Thomas Huxley, “who pioneered analysis into avian origins”
    • Huxley was one of many first to counsel 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 ft
    • 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 kinds of downy feathers on the remainder of its physique
    • Had lengthy feathers on the pinnacle that will have shaped a crest
    • Wing span as much as 20 in (50 cm)
    • Wing had 11 major feathers and 10 secondary feathers, and shaped 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 (in contrast to 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 seem like a four-winged dinosaur (much like Microraptor and Sapeornis)
    • Ft, aside from the claws, had been coated in feathers
    • Foot feathers had been quick and pointed downward
    • A 2010 research checked out melanosomes in Anchiornis feathers and in contrast them to trendy birds
    • Discovered nearly all of its shade (besides the tail, which was lacking)
    • First dinosaur the place we knew its shade was Sinosauropteryx (had a banded orange and white tail)
    • Two predominant kinds of melanosomes: eumelanosomes (black-grey shades, are typically lengthy and sausage-shaped) and phaeomelanosomes (reddish to yellowish, are typically rounder and jelly bean formed)
    • Assist to determine the colours in dinosaurs
    • Research confirmed that Anchiornis had a feathered crest on the pinnacle
    • A lot 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 largely 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 type 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 largely grey, and ft and toes had been black
    • A 2015 research of a distinct Anchiornis specimen discovered solely gray-black melanosomes, with none reddish shade within the crown
    • Attainable that melanosomes had been preserved otherwise or there have been completely different investigative strategies used, or the primary specimen was smaller, and it may very well be the reddish-brown shade obtained changed as Anchiornis grew older. Or may very well 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 steered 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 will 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 might imply that the wing feather association in trendy birds advanced over tens of thousands and thousands of years after which stayed largely 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 raise and drag when moved by means of the air), which might have been thicker than these in trendy birds, growing drag at low speeds and lowering drag at increased speeds
    • Overlapping feathers would make it tough 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 hooked up to a brief rachis”, in all probability used for thermoregulation and repelling water, and mixed with open-vaned wing feathers “would have decreased aerodynamic effectivity”
    • Regarded fluffy
    • In 2019, Yanhong Pan and others, analyzed Anchiornis feathers and located alpha-keratins (normally solely present in trendy feathers) and beta-keratins, modified in a manner 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 largely beta keratins in mature feathers, whereas Anchiornis had beta-keratins and alpha-keratins in its feathers
    • Additional confirmed that feathers might have at first advanced for causes aside from flight
    • Implies 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 advanced for flight
    • Initially thought Anchiornis may fly or glide, however later discovered the wings had been too quick
    • A 2016 research discovered juvenile Anchiornis might have been ready to make use of wings to assist run up hills, and perhaps may fly whereas flapping if utilizing a excessive angle flapping wing stroke, however adults would have been too heavy to fly
    • Flapping whereas working 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 stated 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 “may characterize the plesiomorphic avian situation”
    • Ossified sternum generally lacking in fossil birds. Not having a sternum “counsel that flight capabilities can be severely restricted in basal birds”
    • Present in Anchiornis and Sapeornis, the absence of sternal parts are “a real function of those taxa and never an artifact of preservation or ontogeny”
    • Used histology, discovered all of the specimens to be mature
    • Attainable the gastralia might have supported the muscular tissues wanted for gliding (if it glided), but it surely’s unclear
    • A 2010 research by Alexander and others discovered Anchiornis to be a glider
    • In 2014 Garnet Fraiser steered the lengthy legs of Anchiornis may very well be associated to “dorsal using parasitic habits” (using on the backs of different animals), and used for “working, 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 ft, along with the sickle-shaped second claws
    • Foot pads coated in small, pebble-like scales
    • Had scales on the highest of the ft
    • Some Anchiornis had scales on the toes, tarsus, and decrease leg, so perhaps 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 principally 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 “flippantly 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 recent birds
    • Pellets are undigested components meals which are regurgitated
    • Helps present a digestive system much like trendy birds, “and that the evolution of recent avian digestion might 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 quick 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 vitality for aerial locomotion, and early paravians may even have shortly gotten rid of any non-digested meals, to make themselves lighter shortly
    • Anchiornis was in all probability an opportunistic generalist hunter
    • Presence of three lizard skeletons present in one pellet
    • Fish might 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 stay close to water, it had plenty of feathers under the knee, and it had a comparatively quick snout (normally birds that catch fish have lengthy, slender payments)
    • Fish discovered may imply Anchiornis may 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 embody 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:

    Other than Anchiornis, few fossilized gastric pellets have been discovered with non-avian dinosaurs.

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