Uploaded June 2019 | Updated September 2026, 1 day ago
ATTENTION! Due to some strange issues with Youtube, it has cut out part of the audio from 1:10:24 - 1:12:21. Here is the part of the text that got cut:
Jason: We see he’s got some integument associated with him. Yeah, we’re gonna say that’s fur, but theoretically based off what we decided the criteria for feathers is now, we could also say that those are “feathers”. Just because it’s a long thin cylindrical structure that’s hollow, but okay well… So, it doesn’t help anything.
Once we get down to that monofilament, where things could be “hair” or “feather” it gets really difficult, because it’s a very simple structure to evolve, it’s not that much different from the “spikes” you see on iguanas or even the initial development of the setae that you see on the toes of geckos, cause it’s basically just this long thin structure and it just depends how much beta-keratin you packed on top of it.
So, once things are down to looking like “fur” I think we need to be a lot more careful with what we ascribe to being an ancestral “feather”. I’m sure ancestral feather did start off as that simple structure, but it looks like it came off at a different way, in a way that ultimately overrode scales. Whereas, these other structures (the ones that seem to go in-between scales or closely associated with them) are also very similar (and also very simple), but don’t seem to show that same developmental pattern. Just because we’re seeing scales nearby them means we probably shouldn’t call them “feathers”. Unless somebody can come up with good ultrastructural data that could show otherwise.
AK Rex: There’s a very interesting thing to note in Kulindadromeus, the diagram that they’ve shown. It shows that there is like a branch of them that doesn’t go through those scales. It’s as if it’s branching off and actually coming off of them.
Link to Part 1: youtu.be/bSlLDZsaipM
Links to some of the studies cited in the video (for better research, I recommend googling the bibliography of Danielle Dhouailly, Roger Sawer and Loren Knapp):
onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7580.2008.01041.x
onlinelibrary.wiley.com/doi/full/10.1002/dvdy.20291
Jason's Blog: reptilis.net
ATTENTION! Due to some strange issues with Youtube, it has cut out part of the audio from 1:10:24 - 1:12:21. Here is the part of the text that got cut:
Jason: We see he’s got some integument associated with him. Yeah, we’re gonna say that’s fur, but theoretically based off what we decided the criteria for feathers is now, we could also say that those are “feathers”. Just because it’s a long thin cylindrical structure that’s hollow, but okay well… So, it doesn’t help anything.
Once we get down to that monofilament, where things could be “hair” or “feather” it gets really difficult, because it’s a very simple structure to evolve, it’s not that much different from the “spikes” you see on iguanas or even the initial development of the setae that you see on the toes of geckos, cause it’s basically just this long thin structure and it just depends how much beta-keratin you packed on top of it.
So, once things are down to looking like “fur” I think we need to be a lot more careful with what we ascribe to being an ancestral “feather”. I’m sure ancestral feather did start off as that simple structure, but it looks like it came off at a different way, in a way that ultimately overrode scales. Whereas, these other structures (the ones that seem to go in-between scales or closely associated with them) are also very similar (and also very simple), but don’t seem to show that same developmental pattern. Just because we’re seeing scales nearby them means we probably shouldn’t call them “feathers”. Unless somebody can come up with good ultrastructural data that could show otherwise.
AK Rex: There’s a very interesting thing to note in Kulindadromeus, the diagram that they’ve shown. It shows that there is like a branch of them that doesn’t go through those scales. It’s as if it’s branching off and actually coming off of them.
Link to Part 1: youtu.be/bSlLDZsaipM
Links to some of the studies cited in the video (for better research, I recommend googling the bibliography of Danielle Dhouailly, Roger Sawer and Loren Knapp):
onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7580.2008.01041.x
onlinelibrary.wiley.com/doi/full/10.1002/dvdy.20291
Jason's Blog: reptilis.net
