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Re: On the Issue of Beaks in Avepectorans (Long)



Kris Kripchak (MariusRomanus@aol.com) wrote:
<...[A]sked for something showing similar patterns of the foramina between
the more basal theropods and the later known to be beaked aves. The gull
and swan that was posted on my website was dismissed by you as being
nothing but an oddity (But remember Jaime, that Larsus, as well many
anseriformes, are large birds with correspondingly larger heads more on
the size of the average small theropod).>

  The common gull genus (and I assume the taxon to which the mandbile
belonged) is *Larus* sp., not "Larsus". And rather, I made a very clear
point about rostral foramina in my posts in birds, with several essential
examples, but never did I say there was a definite rule, and am tired of
having this applied to me; rather, I have spoken in generalities and
explicitly so. In anseriforms and apterigiforms, concentrated rostral
foramina are related to probing and sensory behavior, and the bills of
many mergansers and other anatids are fairly soft and not as rigid as in
most landbirds; neognaths for the most part, or at least "neoaveans"
versus galloansereans, have a more rigid beak with reduced foramina. The
geese skulls I have looked at in particular are developed towards a
land-flora and are not as pliable or sensory as anatines or cygnines.
Flamingos, as another given example of a foraminated skull, is also used
in a fairly sensate capacity and the beak is highly vascularized versus
related birds. Primitive neoaveans also, such as gruiforms (members tend
to be probers, especially rails), have more foramina generally in their
rostral bills than do the "advanced" landbirds (passeriforms,
columbiforms, psittaciforms, piciforms, falconiforms, strygiforms and
caprimulgiforms+apodiforms (sensu lato), coraciiforms, etc.). Never made
any more definite reflection on this.

<2. About the medial aspect of the dentary... Do you see a row of foramina
here? Do you believe if there is a row, that it should be dismissed as was
done so by you with the swan?>

  Yet again I am having words shoved down my throat. Point out to me where
I ever said they were pointless or dismissed them? I did explain them. I
feel justified in this manner.

<Do you believe by the evidence given, that the numerous sequential
foramina are not only for the hyolingual musculature, but for said muscles
alone? Are there sequential foramina located on the upper medial aspect of
the dentary that have the sole purpose of innervating hyolingual
musculature?>

  Do yopu beleive that the numerous medial foramina were for the
non-existent medial beak? because if you did, I would certainly like to
see how you could say one or the other was more right. Once again, never
said anything definite, and this goes for the *Dinornis* jaw in topic 1 as
well.
 
<Do you believe if there are sensory branches as well as anastomes here
between the mandibular branch of the trigeminal and the 7th, 9th
hypoglossal and first cervical, that this negates the foramina row shown
as being in any way homologous to the foramina row for the alveolar in
normally toothed regions of theropods?>

  Did I say it did? Or have you seen evidence that shows that the medial
row in these birds is analogous to the lower complex of foramina in
dromaeosaurs? I would like to see evidence of a series transforming the
lateral into a medial set. This burden falls onto you rather than to try
to get someone to explain how these are hyolingual in relationship. Having
looked at birds jaws in anatomical dissection, I am fairly confident that
these medial foramina are not related to the lateral keratinous tissue but
are rather nervous and vascular in nature, for a medial aspect.

<If no, explain how medial rows of foramina then correlate to a non-fused
keratinous covering.>

  Why don't you? This is your theory, disprove it. I have already
explained a non-osteological correlate.

<4. Also, crocs have a keratinous covering where their teeth protrude
through and also have a medial row of foramen. Do these rows in crocs
differ in a way that can show they are not homologous to:>

  As do many mammals, medial and lateral. Humans, for instance, as do
their ancestors, have medial and lateral mental foramina, invaginating the
mandible medial for the root ennervation and exit the lateral mandibular
wall to ennervate the gums; the lips are ennverated by the maxillary
branch, and still the maxilloincisive bone bears external and medial
foramina without a keratinous covering in sight. As for croc keratin in
the gums, I have seen croc jaws and fail to note the gummy and soft tissue
as analogous to a beak. Crocs also have a highly developed lingual
structure.

<a. The same rows seen in toothed theropods?>

  Failing to discard the medial foramina in theropods as a precursor to
that in birds, but rather the lateral to prove a beak? No....

<b. The row shown medially on the swan mandible shown at given address
above?>

  See above. Need to try to answer one's own questions if one is looking
for "proof".

<And also about crocs... Jaime, you said that only "modern" crocodilians
have the extensive pitting for facial â??tactileâ?? surfaces. Is Sues et.
al. in JVP V. 16, n. 1, pg. 35 (paragraph with the skull highlighted)
saying that *Protosuchus micmac* had foramina and pitting like modern
crocodilians or not? (also, *Calsoyasuchus*, JVP 22, n. 3, pg. 593-611.)>

  I most certainly did not say "only modern" crocs, Kris. This is patent
crap. I stated modern crocs and many crocodyliforms and some
crocodylomorphans, and was quite clear on this. It is general, but
tending, as in modern researches, to be sensory related to aquatic
predation and facial sensory organs, not a ceratinized beak. Crocs, for
instance, are the one taxon with pitted armor, this is not an analogous
condition in aetosaurs, or various armored dinosaurs. One sees
non-foraminated pits in the frontoparietal domes of pachycephalosaurids,
but some taxa have a basin-like pitting in the youngest forms that appears
to be unresolved to function or effect. These are not related to foramina,
which are not present in these pits. They may, however, contain
soft-tissue or processes of keratin that anchor to the surface, and many
pits are crossed by channels to other pits (unlike in crocs or croc
armor). But this does not explain the LACK of pits in some taxa, such as
*Stygimoloch* versus the new taxon *Hanssuesia* (for *"Stegoceras"
sternbergi*) which have some extensive and heavy pitting in species at the
same size as those without. The relationshipo of these pits to keratin is
unknown, and basing conclusions on presence or lack of keratin coverage on
the basis of pits, foramina, or rugosities, or lack thereof of either of
those, is not doable. I wish I could get this across, but there seems to
be a lack of willingness to be doubtful. I have no definite conclusions on
this matter, and I am tried of having to defend that statement, largely
because I think the material does not permit one to _be_ definite.

  Maybe trying too hard to get dromaeosaurids with beaks, Lord knows I've
drawn *Velociraptor* with 'em too ever since I read Paul's _PDW_; but
critical review reveals that the evidence is not conclusive on the matter,
so I vacillate and choose to err on the side of caution when examining
this matter scientifically, however I may express myself artistically.
When I originally replied it was with the intent to show the matter was
not definite, but the other side of the debate appears to be personal, and
I won't go there.

<5. Do you see any medial row(s) on the upper jaw in the Moa? If no,
please tell me what you believe it is that I might have perceived.>

  I have photos of several different kinds of moa. Don't think I ever said
the medial row didn't exist. I think I questioned its connection with the
existence of a beak, something I have not yet seen evidence for. The above
few peragraphs also are in response to the further, snipped, leading
comments on the matter. I am asking for a critical self-review of the
data, and apply them, rather than use these observations to try to inflict
a definite on something that never was. If you continue, you never got my
point.

  Cheers, and thanks for the discussion. I would love to see this continue
in a more professional manner, however,



=====
Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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