[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

FEDUCCIA IN AUK/BEAST OF GEVAUDAN



Courtesy Luis, yesterday I received and read Feduccia's 
'Birds are dinosaurs: simple answer to a complex problem' 
(_The Auk_ 119, 1187-1201). If someone writes a rebuttal, 
I suggest they use the same title. It seems there's little point 
in arguing against most of the article, as the author has 
made it fairly clear what he will acknowledge/cite/comment 
on. 

Overall though, it's quite hilarious and here's why: pp. 
1187-1197 explain why dromaeosaurs cannot be, and are 
not, ancestral to/sister-group to birds. Then, pp. 1198, 
Feduccia says dromaeosaurs might be flightless birds. Oh. I 
see. In other words: dromaeosaurs definitely definitely 
definitely cannot be anything to do with birds at all but, by 
the way, they might be birds. As many have noted by now, 
the idea that some maniraptans might be birds but that, 
nevertheless, birds are not part of Dinosauria is as 
defensible as saying that humans are not primates.
 
Other things...

-- Much discussion and a table show how theropod and bird 
teeth are fundamentally different. Even if this is true, so 
what? Evolution. One can easily marshall a huge list of 
features showing how radically different humans are from 
other great apes, thus humans cannot be apes.

-- Carpals: he states that _Archaeopteryx_ has four carpals 
and that the semilunate is a single carpal, not a compound 
element. Old argument. In addition to the semilunate, 
_Archaeopteryx_ seems to have two carpals (and I was 
actually looking at _Archaeopteryx_ yesterday in the NHM 
collections).. well, this is the same as bird-like theropods 
(though three carpals in addition to the semilunate have 
been suggested for _Microraptor_). It still makes no sense 
why Feduccia argues that the bird semilunate cannot be 
homologous with that of other maniraptorans.

-- Hands. Fair enough, this is still controversial even though 
the frame-shift hypothesis has proposed an answer. But 
what seems philosophically difficult is Feduccia's position 
that 'if one key synapomorphy were falsified, it would 
reduce all the other synapomorphies to the status of 
parallelism or homoplasy'. He cites Howgate (1985) for 
this! I really don't understand the logic here. How do we 
know when examing characters which proposed 
synapomorphy is the 'one key'? And as we know, even 
assuming that non-avian theropods and birds DO have 
different digital formulae, birds still fall within Theropoda.

-- On 'dino-fuzz' he draws analogy with the internal skin 
fibres described on ichthyosaurs by Lingham-Soliar. This is 
seriously misleading for a host of reasons and in fact the 
ichthyosaur fibres do not resemble those of the theropods in 
detail. See...

http://www.cmnh.org/dinoarch/2002Aug/msg00090.html

Here is a critique of this notion from personal 
correspondence...

----------------------------------
RE: skin fibres/integument.
In the ichthyosaurs the fibres can be seen to either overlay 
bone or clearly be _within_ (viz, medial to) the external 
skin surface. Furthermore they look nothing like the 
structures seen on the theropods: the only ones that _do_ are 
arranged in an orthogonal meshwork and are preserved as 
overlapping layers that, again, were clearly embedded 
within the dermis. Structurally these fibre meshworks are 
interpreted by Lingham-Soliar (the describer of these 
structures) as analogues of the cross-fibre arrays seen in 
sirenian, cetacean and shark skin. Because such cross-fibre 
arrays appear to have evolved as a means of keeping the 
skin strong, flexible and smooth there is no reason to expect 
such fibre types in terrestrial vertebrates like dinosaurs and 
indeed, similar structures are not seen in other vertebrates.

The fibres in the theropods are clearly _external_ to the skin 
(even in _Sinosauropteryx_ where a layer of resin has been 
misinterpreted as an epidermal impression by certain 
workers), exhibit a definite tufted or branching morphology 
and exhibit barbs in NGMC 91 and _Cryptovolans_. In 
NGMC 91 the fibres extend for a substantial distance 
beyond the skeleton and in this and the other fibre-bearing 
theropods these structures appear morphologically 
identifical to the fibres (i.e., not the remiges and rectrices) 
of _Caudipteryx_. The simple parsimonious conclusion is 
that these theropods therefore possessed integumentary 
'fuzz' similar (superficially at least) to that of ratites.
----------------------------------

-- He argues that dinosaurs have a fantastic fossil record and 
that therefore the idea of Jurassic ghost lineages for 
Cretaceous maniraptorans is implausible. He argues that 
because hundreds of Jurassic coelophysoid skeletons are 
known (p. 1197) then the absence of Jurassic proto-bird 
dinosaurs is evidence of absence. Morrison Fm 
maniraptorans are said to be nothing more than 
'unidentifiable trash'. None of this gets round the fact that 
Jurassic small theropods are very poorly represented due to 
assorted sampling/palaeobiogeographical regions, 
something he refuses to acknowledge. The absence of 
evidence here (good evidence) is a weakness though: can 
someone please go out this weekend and find a mid-Jurassic 
lagerstatte full of small coelurosaurs please?

-- Feduccia seems not to be aware of any work done on non-
avian archosaur phylogenetics since the time of Romer, nor 
on the distribution of characters. He indicates that 
_Ornithosuchus_, _Postosuchus_, _Lagosuchus_ (ignorance 
is bliss) and _Lagerpeton_ pose problems for dinosaur and 
archosaur phylogeny, again without citation of any of the 
stacks of work done on these forms; follows Chatterjee 
(1985) in implying that _Postosuchus_ is strongly theropod-
like; and cites Welman (1985) on the alleged birdiness of 
_Euparkeria_. It is academically dishonest to cite works like 
these when there are substantial, more recent reappraisals.. 
or am I wrong in assuming that he is up to date with the 
literature? Of Dinosauria, he even writes that there has been 
'extreme difficulty in defining this important clade' (oh 
really?) and writes that 'if the thecodonts can be termed a 
'garbage bag assemblage', then why not the Dinosauria'. 
This makes no sense whatsoever... exactly like saying 'If 
Gaviomorphae [polyphyletic group including 
hesperornithiforms, loons and grebes] is a garbage bag, 
what about Passeriformes?'.

In the interests of free speech, Feduccia should of course 
continue to say what he likes. But while this article and 
others like it will never be cited by anyone excepting three 
or four select authors, we must still consider that those who 
are not specialists in this field might take his comments at 
face value. A quote I half-remember from an article on the 
spread of creationism in Turkey was "If intelligent people 
keep quiet, it only helps those who spread nonsense".

----------------------------------

And now to something seriously off topic but re: 
_Brotherhood of the Wolf_, the take in this film is that the 
Beast of Gevaudan was an African wolf-like carnivoran 
kitted out with a suit of armour (!). It was not intended to be 
living creodont (though, it has been suggested it in the 
literature that it was a surviving _Machairodus_; however, 
has also been suggested it was a hitherto unknown giant 
giant mustelid or a werewolf). 

Of course the real Beast of Gevaudan (which attacked 
people throughout Gevaudan, France, between 1764 and 
1767) is still something of an enigma - it is implicated from 
the white marking on its chest and the fact that it wagged its 
tail as it attacked people that it was a trained dog or 
dog/wolf hybrid (this is Jean-Jacques Barloy's theory; IIRC 
he is interviewed about this on the _Brotherhood of the 
Wolf_ DVD). However, the skin of the animal killed by 
Antoine Chastel (sent to kill the beast by Louis XV in 1765) 
was recently rediscovered in the collections of the NMNH, 
Paris, and is a striped hyaena (_Hyaena hyaena_). Because 
attacks and sightings continued after 1765, this animal 
cannot have been solely responsible though.

See...

Jullien, F. 1998. La deuxieme mort de la bete du Gevaudan. 
_Annales du Museum du Havre_ 59, 1-9.

I didn't think the dubbing was so good, plus all the fight 
scenes were a bit daft. 

-- 
Darren Naish
School of Earth & Environmental Sciences
University of Portsmouth UK, PO1 3QL

email: darren.naish@port.ac.uk
tel: 023 92846045