Comments on: What on Earth are pycnofibers?

By: W skrócie (5) – przegląd nowych prac, artykułów i książek

W skrócie (5) – przegląd nowych prac, artykułów i książek — Sat, 05 Feb 2011 12:06:23 +0000

[...] skórnej pterozaurów. [doi: 10.1098/rspb.2009.0846; dyskusja na Forum Dinozaury.com!; wpis Dave Hone'a na blogu "Dave Hone's Archosaur Musings"; artykuł na "Discovery News" i w "National Geographic"]. 6. Junchang Lü, David M. Unwin, [...]

By: David Hone

David Hone — Wed, 03 Nov 2010 15:19:39 +0000

Yes, that’s a typo. It should of course read more as “….keratin, like scales, feather and hair”.

By: Monad

Monad — Wed, 03 Nov 2010 15:10:39 +0000

Hi Dave – I was reading the Jeholopterus paper you authored with Kellner and several others and it states with regards to pycnofibres that “They were possibly mostly composed of
keratin-like scales, feathers and mammalian hair.” This seems to have confused some people:

http://dml.cmnh.org/2009Aug/msg00309.html

but I’m guessing just a typo – hyphen in the wrong place?

By: Yet another UV Archaeopteryx – this time out: Daiting « Dave Hone’s Archosaur Musings

Fri, 05 Mar 2010 00:29:14 +0000

[...] for study however and my friend and colleague Helmut Tischlinger (he of UV Archaeopteryx-es, pterosaurs and Microraptor) has done an initial description, topped, inevitably with some beautiful [...]

By: Microraptor in UV and feather attachment « Dave Hone’s Archosaur Musings

Sat, 13 Feb 2010 00:56:42 +0000

[...] trip to China which involved lots of UV light work. Some of that has already turned up in print via Jeholopterus but constraints in paper length meant we did not get to include everything we would have liked to [...]

By: Musings on 2009 « Dave Hone’s Archosaur Musings

Musings on 2009 « Dave Hone’s Archosaur Musings — Wed, 30 Dec 2009 01:35:50 +0000

[...] members of the pterosaur research team from Karlsruhe made it over and thus kept me busy while the Jeholopterus paper finally made it’s formal existence known, though it was in press in [...]

By: David Hone

David Hone — Fri, 07 Aug 2009 14:47:53 +0000

It may sound like a cop-out but this isn’t – Dave you know well that by definition not every author writes every bit of every paper or necessarily agrees with everything in it. As such, you really need to speak to Alex about this, not me.

I would say though that we were well over the page limit for a Proc R Soc B paper and had to cut things out as well as pay the extra page charges. It’s not easy to cram in that much of a redescription and then cover all the implications of wing structure, preservation, claws, actinofibrils, pycnofibers etc.

In any case I think the points you raise here are not mutually exclusive: we can hardly examine the homology (or otherwise) of various strucutres without a good understanding of their evolution and structure. As such, the identification of the composition of pycnofibers can hardly not have important implications for working out the homologies – just becuase they share soem features does not make them necessarily homolgous (depending on your level of homology of course – at one very deep level hairs are likely to be homologous with feathers). In short I don’t see the contradiction between pycnofibers having a similar composition to feathers and not actually being homologous with feathers.

By: Dave Unwin

Dave Unwin — Fri, 07 Aug 2009 09:43:09 +0000

Dave,

I’ve been through the Jeholopterus soft tissue paper and found it very confusing.

Just to get the ball rolling, here are a couple of lines from page 6, para 1:

This is a very interesting claim that has important implications for the origin and homology of pterosaur ‘hair’ although, so far as I can tell, these implications are not discussed in the paper. More importantly, there does not appear to be any visible evidence for this ‘composite’ morphology in the illustrations and no further details are given in the paper. So, what exactly is the basis for this claim?

How is this possible? Elsewhere in the paper you cast doubt on any homology with protofeathers.

By: David Hone

David Hone — Fri, 07 Aug 2009 02:47:47 +0000

Hi Christopher, thanks for your questions but I am sorry to say that I can’t really answer them since I have not examined the specimen in sufficient detail to really say so and i don’t want to put words into Alex’s mouth by speaking about how he interprets the material. I’ll see if I can get him on here to post an answer for you.

By: Christopher Collinson

Christopher Collinson — Fri, 07 Aug 2009 02:14:05 +0000

Dave, after reading the paper I have couple of questions. First when you say that the tenopatagium was “extensively covered
by elongated and thick fibres here called pycnofibres.” Are you meaning to say that the pycnofibres were originating from the membrane or that the pellage of the body was just sort of sticking out laterally and overlying the proximal portion of the membrane? Secondly, could you provide more insight into the individual structure of the pycnofibres? They are said to be “further formed by smaller fibrils.” But how exactly are the smaller fibrils arranged, and why is it clear that is so?

Thanks.

By: David Hone

David Hone — Thu, 06 Aug 2009 08:31:27 +0000

Well I am glad it entertained someone!

By: Taissa

Taissa — Thu, 06 Aug 2009 07:55:53 +0000

I am still laughing with the name PIS. =D

By: David Hone

David Hone — Thu, 06 Aug 2009 05:58:34 +0000

Well the public perhaps, but this should solve the issue for palaeontologists and it helps keep things clear which is a large part of the point.

By: mythusmage

mythusmage — Thu, 06 Aug 2009 05:41:38 +0000

You do realize people are going to call it hair and fur anyway. There are popular terms and there are correct terms, and they’re not always the same.

By: Tim Morris

Tim Morris — Thu, 06 Aug 2009 03:18:39 +0000

Somehow, greg paul’s outdated musings about “dinosaurs not extinct if there were mouse sized forms” sound like a load of hooey.

By: David Hone

David Hone — Thu, 06 Aug 2009 00:26:03 +0000

No but I’ll get it out as soon as I have a copy.

By: Zach Miller

Zach Miller — Wed, 05 Aug 2009 16:40:51 +0000

Found it. It’s under “FirstCite,” but it’s not freely available. *sigh*

By: Zach Miller

Zach Miller — Wed, 05 Aug 2009 16:39:17 +0000

Bah–I keep forgetting about that pterosaur volume, too!

Sounds like a great paper, but your link at the end of the post is busted, and a look at the “current issue” of Proc. Roy. Soc. B reveals no pterosaur paper…

By: David Hone

David Hone — Wed, 05 Aug 2009 14:40:23 +0000

No but I think the burden of proof should be to provide homology than prove non-homology. Given the uncertain phylogenetic position of pterosaurs and (even if they are ornithodires) the gap between them (phylogenetically and temporally) and protofeathered dinosaurs, I think it’s safer to assume they are not homologous at this point.

By: David Marjanović

David Marjanović — Wed, 05 Aug 2009 14:31:56 +0000

Nor (despite some calls for it) could they be considered protofeathers as there is no established homology between them and saurischian protofeathers and feathers (or for that matter ornithischian dermal structures).

Does the paper demonstrate nonhomology, though?