Episode 458: Past Bones: Feathers

Episode 458: Past Bones: Feathers. Plus a mammal discovered fossilized on prime 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) fashionable birds molt at the very least annually, however Mesozoic dinosaurs could have molted much less ceaselessly 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)
• Appeared 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 virtually 2 ft 5 in to almost 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) that will have been partly reversed/backward going through and had physique proportions like fashionable flightless birds
• Most likely might perch, like some fashionable birds
• Like early birds and the oviraptorid Heyuannia, had a brief third finger on its arms
• Had quick claws on its arms
• Hand is longer than both the humerus or radius (arm bones)
• Had lengthy legs, and possibly was a quick runner
• Regarded as secondarily flightless (advanced from animals that would fly)
• Had a extremely developed wishbone, or furcula, like fashionable 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 arms (between virtually 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 saved it heat
• In 2018, Yaser Talori and others experimented with a robotic Caudipteryx with practical wing proportions to check if the feathers on the wings helped it run sooner
• Discovered that if wings had been fastened and prolonged out, would have solely helped with small quantities of raise and drag. Identical with flapping whereas operating
• Primarily based on outcomes, discovered that its feathers had been in all probability for show
• Presumably 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 velocity 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 assist that flapping advanced lengthy earlier than feathered dinosaurs might fly (flapped whereas operating on the bottom)
• Most likely omnivorous, although probably an herbivore
• Presumably ate bugs and vegetation
• 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 probably herbivorous
• Two species: Caudipteryx zoui and Caudipteryx dongi
• Sort species in Caudipteryx zoui
• Genus title 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 title “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
• Practically full skeleton present in 1998, with effectively 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 could have been capable of perch
• Had pores and skin impressions on the arms and arms, and “the pores and skin doubles the width of the digits when the animal was alive”
• Species title “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 plenty 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 advanced 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 (plenty of discussions since, and had been in contrast with oviraptors and flightless birds)
• When Caudipteryx was described, it was thought to offer 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 controversy 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 fashionable 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 usually are 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 utterly articulated)
• One referred to Caudipteryx zoui, the opposite an indeterminate species
• Discovered plenty of birdlike options however nonetheless discovered it to be a feathered dinosaur
• Discovered hallux is at the very least partially reversed (backward), so ancestor of Caudipteryx in all probability was in a position to hang around in bushes
• 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 (delicate tissue!)
• Demineralized the fabric and stated it “exhibits beautiful preservation”
• Discovered chondrocytes, which preserve cartilage and one had a nucleus and “fossilized threads of chromatin” (which is a mixture of DNA and proteins that kind 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 knowledge present that a few of the unique nuclear biochemistry is preserved on this dinosaur cartilage materials and additional assist the speculation that cartilage could be very susceptible 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 vegetation, and even embryo-like fossil cell clusters which might be greater than 600 Million years (My) previous”)
• Additionally stated current taphonomy experiments on vegetation 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 delicate 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 relating to self destruction of cells and tissues (often known as autolysis) which helps fossilize nuclei, and calcified cartilage appears to be much more decay resistant, so it’s not stunning that fossilized calcified cartilage has “distinctive mobile and nuclear preservation […] whatever the age of the fossil”
• Could take a couple of weeks for chondrocytes to decay after an animal dies, which implies to ensure that nuclear preservation in cartilage, the animal doesn’t must 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 regardless that DNA is outwardly in a non-PCR amplifiable and non-sequenceable kind in Mesozoic fossils, a few of 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, regardless that a DNA sequence has by no means been authenticated in any fossil a lot older than ~1.2 My. Though the outcomes offered listed below are preliminary chemical knowledge, they nonetheless assist the speculation regarding DNA fossilization merchandise and reaffirm that rather more efforts must 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 Reality:

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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