Comments on: Dramatic restructuring of dinosaur feathers revealed by two youngsters of same species

By: heleen

heleen — Sat, 27 Oct 2012 23:09:46 +0000

About the “half-ribbon feathers”.
During moult, long feathers have a coating to bundle them up, and the vanes are spreading out from the top down. Are the “half-ribbon feathers” not simply pennaceous feathers caught in their first growth during moulting?

By: Brian Too

Brian Too — Mon, 03 May 2010 03:37:07 +0000

Amazing stuff coming out of China these days. They seem to be leaders in the area of feathered dinosaurs (both discovery and analysis).

By: Zach Miller

Zach Miller — Fri, 30 Apr 2010 19:50:08 +0000

Dan, given the analogy to modern birds going through several moults, I think the more reasonable answer for now is that the younger animal really is a younger animal at a different plumage stage. It would be telling if somebody looked at the feathers of “Dave” (usually considered a juvenile Sinornithosaurus) and then compared it to the feathers of adult fossils.

To answer Mike’s question, the functional aspect of arm-feathers in non-avian dinosaurs has always been up for debate. Prey capture probably has little to do with it. You may be referring to Ostrom’s old idea that Archaeopteryx used its wings as “bug-catching” scoops. This most certainly did NOT occur. It’s more likely that large arm feathers actually hindered prey capture. I would expect that large predatory maniraptors (like dromaeosaurines) had reduced manual and arm feathers. Some of the more interesting “reasons” for arm feathers that I’ve read have been parachuting or flying (ancestrally), brooding, and sexual display. I can’t imagine why all three of these functions couldn’t have overlapped, either.

Notice, also, that pennaceous feathers are unique to “higher” maniraptors. Alvarezsaurs and therizinosaurs didn’t have pennaceous feathers, at least not on their arms. I don’t think there’s good evidence that oviraptorosaurs were carnivorous, so maybe their long hand and arm feathers didn’t get in the way when feeding.

By: Dan Kushner

Dan Kushner — Fri, 30 Apr 2010 14:57:49 +0000

While I agree that the evidence could suggest that this dinosaur changed their feathers over its lifetime, isn’t it shortsighted to jump to that conclusion. The article mentions that finding these juvenile fossils is incredibly rare, so how can we speak for the species based on two individuals.

It is equally likely that these two types of feathers are simply two difference phenotypes (physical traits) of the same species. Genetic variations can be found in this population, so the younger dinosaur could have inherited a different feather gene than the older dinosaur. It doesn’t necessarily mean that an individual’s feathers change over time.

By: Lilian Nattel

Lilian Nattel — Fri, 30 Apr 2010 14:39:36 +0000

I’ve watched countless Land Before Time videos with my kids. I wonder if the producers are keeping up with your blog!

By: Daniel J. Andrews

Daniel J. Andrews — Fri, 30 Apr 2010 04:26:47 +0000

such as sonic hedgehog (don’t ask – developmental biologists make their own fun)

Ah, but the story behind the names is sometimes part of the fun for others. E.g. the gene named “indy” which when mutated doubles the lifespan of the fruit fly. The name is an acronym for I’m Not Dead Yet–referring to a running joke from Monty Python and the Holy Grail…and if you haven’t seen that film, then you simply must. How can you understand what goes on in science if you haven’t almost memorized the dialogue from that film?

Interesting how the primary feathers number 10, same number as most passerines, and many non-passerines.

By: Mike McK

Mike McK — Thu, 29 Apr 2010 20:15:25 +0000

This is peripheral to the development question, but is related to the feather discussion.

The more senior specimen has arm feathers that really are similar to the superficial aspects of current wings. The pictures indicate that these were agile runners and they certainly have claws. How do the wing-like feathers fit in terms of function, whether in capturing prey or in some other way?

By: DK Fennell

DK Fennell — Thu, 29 Apr 2010 12:31:05 +0000

Would love to see the chart with feather morphologies and dino phylogeny that Nature teases us with in the abstract, but Nature purposely has it at such a resolution that one can’t read it. Oh well, I guess that’s why God created libraries — for us impoverished types who can’t afford all the subscriptions required.
BTW, slightly off topic, but related to your earlier guest column on science reporting and getting both sides, I was slightly taken aback by a reaction published in the Nature News roll out of the piece. It quotes “developmental biologist” Cheng-Ming Chuong from the University of Southern California in Los Angeles, who begins the assessment with “If we give [the?] authors the benefit of doubt …” Perhaps this was a poor choice of words, but it seems to me that it falls in the category of “unnecessarily confrontational.” Wouldn’t it have been better to say “based on what I’ve seen in the paper”? After all if Xing Xu isn’t entitled to the “benefit of the doubt” on feathers, then I guess science discussions on the net have descended to the level of political discussions on the net.

By: Ed Yong

Ed Yong — Wed, 28 Apr 2010 21:22:35 +0000

And bear in mind that the young Similicaudipteryx isn’t exactly a “chick” so it might well have gone through a downy stage. In modern birds, after the initial moult that gets rid of the downy birth-feathers, the animal has the same structure of feathers for the rest of its life. These fossils suggest that feather structure continued to change in dinosaurs, making at least one further transition from ribbons to quills.

By: Walter S. Andriuzzi

Walter S. Andriuzzi — Wed, 28 Apr 2010 21:18:57 +0000

@ Amy Heller
Dinosaurs: ribbons –> quill-like
Modern birds: downy feathers –> fully-fledged
Both change, but not in the same way, hence “a way we don’t see in any modern bird”