Episode 458: Past Bones: Feathers

Episode 458: Past Bones: Feathers


Episode 458: Past Bones: Feathers. Plus a mammal discovered fossilized on high of (and certain preventing) a Psittacosaurus

Information:

  • A brand new recreation of the colour on Wulong’s spectacular feathers supply
  • Beetles present in amber munching on cretaceous dinosaur feathers supply
  • 2004 paper concerning the first ever parasitic louse discovered within the fossil report (which was consuming dinosaur feathers) supply
  • Most (perhaps all) trendy birds molt not less than yearly, however Mesozoic dinosaurs might have molted much less continuously supply

The dinosaur of the day: Caudipteryx

  • Basal oviraptor theropod that lived within the Early Cretaceous in what’s now Liaoning Province, China (Yixian Formation)
  • Regarded very birdlike, coated in black downy feathers, with lengthy legs, a protracted neck, quick arms with feathers on it, tail feathers, and a rounded snout
  • Peacock sized
  • Estimated to be nearly 2 ft 5 in to just about 3 ft (about 0.7 to 0.9 m) lengthy and weigh 11 lb (5 kg), primarily based on its femur
  • Very gentle, with delicate bones
  • Had a box-like cranium
  • Had giant eyes
  • Had a brief snout and never many tooth
  • Had small, weak tooth
  • Had a hallux (first toe) which will have been partly reversed/backward going through and had physique proportions like trendy flightless birds
  • Most likely might perch, like some trendy birds
  • Like early birds and the oviraptorid Heyuannia, had a brief third finger on its fingers
  • Had quick claws on its fingers
  • Hand is longer than both the humerus or radius (arm bones)
  • Had lengthy legs, and doubtless was a quick runner
  • Regarded as secondarily flightless (developed from animals that would fly)
  • Had a extremely developed wishbone, or furcula, like trendy birds
  • Wishbone much like Archaeopteryx, Confuciusornis, and different non-avian theropods
  • In 2019, Arindan Roy and others discovered the feathers of Caudipteryx to be black and the tail feathers to have a banding sample
  • Had a brief tail that was stiff towards the tip/finish, much like birds and oviraptorosaurs
  • Had a fan of feathers on its tail
  • Had feathers with vanes and barbs on its fingers (between nearly 6 to eight in or 15 to twenty cm lengthy)
  • Had longer, symmetrical feathers on its arms and tail, in all probability for show or brooding (symmetrical feathers means it couldn’t fly)
  • Downy feathers in all probability stored it heat
  • In 2018, Yaser Talori and others experimented with a robotic Caudipteryx with real looking wing proportions to check if the feathers on the wings helped it run quicker
  • Discovered that if wings had been fastened and prolonged out, would have solely helped with small quantities of elevate and drag. Similar with flapping whereas operating
  • Primarily based on outcomes, discovered that its feathers had been in all probability for show
  • Probably helped with turning, like ostriches do
  • In 2019, Yaser Talori and others re-examined how Caudipteryx used its feathers and used the robotic once more
  • Estimated the max operating pace to be about 8 m/s (meters per second)
  • Discovered that whereas operating, there would have been some compelled vibrations that taught it to flap its wings
  • In 2022 Jing-Shan Zhao and others, together with Yaser Talori, went again to the Caudipteryx robotic and located extra help that flapping developed lengthy earlier than feathered dinosaurs might fly (flapped whereas operating on the bottom)
  • Most likely omnivorous, although presumably an herbivore
  • Probably ate bugs and crops
  • Two people have been discovered with gastroliths
  • Had a protracted neck, with ten vertebrae (later one particular person discovered with 12 vertebrae)
  • Primarily based on the neck and gastroliths, regarded as presumably herbivorous
  • Two species: Caudipteryx zoui and Caudipteryx dongi
  • Sort species in Caudipteryx zoui
  • Genus identify means “tail feather”
  • Named by Ji Qiang and others in 1998
  • A number of skeletons have been discovered, and first bones present in 1997
  • Sort specimen discovered was near mature when it died, primarily based on fusions and ossifications within the bones
  • Species identify “zoui” refers to “Zou Jiahua, vice-premier of China and an avid supporter of the scientific work in Liaoning”
  • Second species, Caudipteryx dongi, named in 2000 by Zhong-He Zhou and Xiao-Lin Wang
  • Almost full skeleton present in 1998, with properly preserved wing feathers, practically full arms, hindlimbs, and pelvis (no cranium)
  • Extra articulated than the sort species, and was a big particular person
  • Caudipteryx dongi had a comparatively lengthy higher half of the pelvis, in comparison with Caudipteryx zoui, and smaller sternum (center a part of chest)
  • Had a brief first toe (hallux) that faces backward, so might have been capable of perch
  • Had pores and skin impressions on the arms and fingers, and “the pores and skin doubles the width of the digits when the animal was alive”
  • Species identify “dongi” “refers to Zhiming Dong, a distinguished Chinese language dinosaur knowledgeable”
  • Not all scientists assume Caudipteryx is an oviraptor
  • Some scientists assume it was a hen
  • Due to Caudipteryx, there’s been a lot of debate about how birds and dinosaurs are associated
  • In 1998 when Caudipteryx was named, there was debate on the origin and evolution of early birds and whether or not they developed from coelurosaurian theropods
  • When named, authors stated Caudipteryx represents “levels within the evolution of birds from feathered, ground-living bipedal dinosaurs”
  • Clump of feathers preserved on the chest
  • Authors named Caudipteryx primarily based on two practically full, partially articulated skeletons with feather impressions on the arms, tail, and physique (present in 1997). Initially regarded as a maniraptoran that’s nearer to birds than different dinosaurs (a lot of discussions since, and had been in contrast with oviraptors and flightless birds)
  • When Caudipteryx was described, it was thought to supply the primary proof of feathers in dinosaurs. However Zhou and Wang wrote: “This opinion, nonetheless, has been challenged by many paleornithologists who counsel that Caudipteryx was in all probability a flightless hen, a “Mesozoic kiwi””
  • Within the paper naming Caudipteryx dongi, interpreted Caudipteryx as a feathered dinosaur, however authors stated “we consider the talk on the dinosaurian or avian state of Caudipteryx and oviraptorids will proceed”
  • In 2000, Jones and others stated Caudipteryx was a flightless hen, primarily based on evaluating physique proportions of flightless birds and non-avian theropods
  • In 2002, Teresa Maryanski and others discovered Caudipteryx to be each oviraptor and hen (had feathers, oviraptors discovered to brood eggs)
  • In 2005 Gareth Dyke and Mark Norell discovered Caudipteryx to be a non-avian theropod and never a flightless hen
  • Proportions of leg bones and middle of mass are extra much like trendy operating/cursorial birds than non-avian theropods, which is why some scientists discovered it to be a flightless hen
  • Dyke and Norell argued that the conclusion that Caudipteryx was a flightless hen was primarily based on the belief that birds are usually not associated to non-bird theropods
  • Lawrence Witmer stated, “The presence of unambiguous feathers in an unambiguously non-avian theropod has the rhetorical influence of an atomic bomb, rendering any doubt concerning the theropod relationships of birds ludicrous.”
  • In 2000, Xiaolin Wang and others studied two new specimens of Caudipteryx (every had skulls and had been practically fully articulated)
  • One referred to Caudipteryx zoui, the opposite an indeterminate species
  • Discovered a lot of birdlike options however nonetheless discovered it to be a feathered dinosaur
  • Discovered hallux is not less than partially reversed (backward), so ancestor of Caudipteryx in all probability was ready to hang around in timber
  • Specimens are barely smaller than the opposite ones discovered
  • However their leg to arm ratio was smaller than the bigger specimens, which can imply the arms developed sooner than the legs
  • In 2021, Xiaoting Zheng and others studied cartilage of Caudipteryx (smooth tissue!)
  • Demineralized the fabric and stated it “reveals beautiful preservation”
  • Discovered chondrocytes, which keep cartilage and one had a nucleus and “fossilized threads of chromatin” (which is a mixture of DNA and proteins that type the chromosomes present in cells), and stated it “retained a few of their unique chemistry”
  • Mentioned it was the second instance of fossilized chromatin threads. First one was present in cartilage of the hadrosaur Hypacrosaurus
  • Paper stated, “These information present that among the unique nuclear biochemistry is preserved on this dinosaur cartilage materials and additional help the speculation that cartilage could be very liable to nuclear fossilization and an ideal candidate to additional perceive DNA preservation in deep time”
  • Authors stated nuclei thought to degrade shortly after loss of life, however there are many fossil tissues with preserved nuclei (“from permafrost-preserved Cenozoic mammals, Mesozoic dinosaurs, numerous Cenozoic, Mesozoic, and Paleozoic crops, and even embryo-like fossil cell clusters which might be greater than 600 Million years (My) previous”)
  • Additionally stated current taphonomy experiments on crops and algae confirmed nuclei to be extra secure and decay slower than beforehand thought
  • Cartilage present in mammals “is among the most sturdy and decay resistant smooth tissues of the physique”, as a result of it’s shielded by surrounding tissues, there’s no vascularization (blood vessels), which protects from microbial invasions, and has a “low cell density and its cells have an anaerobic metabolism” (no oxygen)
  • Chondrocytes have a delay on the subject of self destruction of cells and tissues (often called autolysis) which helps fossilize nuclei, and calcified cartilage appears to be much more decay resistant, so it’s not shocking that fossilized calcified cartilage has “distinctive mobile and nuclear preservation […] whatever the age of the fossil”
  • Could take just a few weeks for chondrocytes to decay after an animal dies, which suggests to ensure that nuclear preservation in cartilage, the animal doesn’t have to be buried instantly
  • In contrast Caudipteryx to a rooster and located similarities
  • Primarily based on the chemistry of the tissues and surrounding sediments, discovered iron and different supplies helped within the preservation, and these different supplies are widespread within the Jehol Biota (although the iron got here later)
  • Discovered a cartilage cell nucleus (which has genetic materials)
  • “A few of the unique nuclear biochemistry is preserved on this dinosaur cartilage materials”
  • “It was not too long ago proposed that though DNA is seemingly in a non-PCR amplifiable and non-sequenceable type in Mesozoic fossils, among the unique chemistry and molecules should still be preserved within the type of DNA fossilization merchandise. This may occasionally clarify why some dinosaur cells can nonetheless react with DNA stains, though a DNA sequence has by no means been authenticated in any fossil a lot older than ~1.2 My. Though the outcomes introduced listed here are preliminary chemical information, they nonetheless help the speculation regarding DNA fossilization merchandise and reaffirm that rather more efforts have to be made to research all of the unanswered questions on DNA preservation in deep time, particularly in fossilized cartilage.”
  • Different dinosaurs that lived across the identical time and place embody the tyrannosauroid Dilong and the dromaeosaur Sinornithosaurus

Enjoyable Truth:

Small mammals typically attacked a lot bigger dinosaurs within the Mesozoic. A brand new fossil appears to indicate a Repenomamus (a mammal) attacking a Psittacosaurus.

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