Re: Klaus Ebel's aquatic Saurischia (and much more)

["David Marjanovic" <david.marjanovic@gmx.at>]

(Is there anyone in theropod@yahoogroups.com who is not also here?)

So Brian Choo found Ebel's site... long ago, Ebel contacted me, we talked a
little, he pointed me to his website, and I was pretty shocked. I wrote very
long comments in 2 e-mails, then the computer crashed, and the e-mails are
probably destroyed... I'll have to repeat the whole exercise (but this time
probably in public, on a website, now that "everyone" knows about it),
_sometime_ when I get some time on my hands.
        In _short_, Engineer Ebel is right that terrestrial vertebrates have
the problem of preventing the vertebral column from hanging through. He's
also partly right that not a lot of research has been done on that. But all
the rest is wrong.

----- Original Message ----- 
From: "Nicholas Gardner" <ratites637@hotmail.com>
To: <dinosaur@usc.edu>; <theropod@yahoogroups.com>
Sent: Saturday, July 19, 2003 3:59 PM

> >http://www.ebel-k.de/dinosaurs1/dinosaurs2/dinosaurs2.html

Begin with dinosaurs1/dinosaurs1.html.

> I think the principle error throughout the paper stems from that Ebel is
> trying to insist that because the adaptions for terrestrial locomotion in
>>
> QUADRUPEDAL << ungulates and the freakish pseudosuchian _Ctenosauriscus_
> (tall neural spines of the anterior dorsal vertebrae) were absent in
> theropods, this indicates that they could not have been terrestrial
> locomoters.

Yeah. In more precise words, IMHO, his principal problems are a) not getting
the idea that there could be several solutions to the same problem, b) not
knowing that such different solutions indeed exist, and c) not
differentiating between "the same problem" and "more or less the same
problem".
        Beginning with c), all those ungulates, unlike almost all dinosaurs,
- are totally front-heavy,
- have very mobile shoulder girdles that must be held together by something
mobile like muscles and ligaments,
- and they have a second reason for elongating their cranial dorsal
spines -- making an attachment site for the ligaments that hold the heavy
head which hangs +- vertically during grazing, drinking etc. but is raised
to a horizontal position otherwise.
        Considering b), it has turned out that Ebel had absolutely no idea
of the hyposphene-hypantra articulations of most saurischians. Their purpose
is to... bingo! prevent the vertebral column from hanging through. The same
can be said of the ossified tendons of most ornithischians. In addition, the
neural spines of dinosaurs are commonly highest over the hip, which is
precisely what Ebel should expect.

In short, Ebel tries to argue from ignorance instead of from knowledge.
:-( :-( :-(

> How does Ebel deal with terrestrial squamates and pseudosuchians
> that were not aquatic and lack tall neural spines?

Small terrestrial squamates... too small to really feel the effects. (No
calculations whatsoever about how small small is.) Big terrestrial
squamates, namely the Komodo monitor... sorta kinda partly semiaquatic,
which relieves them from the need of supporting their vertebral column,
apparently even when they're not in the water, or something of that sort
~:-| . Crurotarsans? He doesn't mention them. And likely he hardly knows
them.

>  Or that the neural spines were elongated in many sauropod taxa . . .

This he simply doesn't know. Of course how elongated is elognated...

In addition, Ebel ignores evolutionary ecology. All those dinos are supposed
to have been aquatic for 150 and more Ma, to have lived in open shallow seas
(as opposed to small mountain streams like dippers) and not evolved any
adaptations to that lifestyle? Just won't happen.

> He also presents outdated reconstructions of both _Ouranosaurus_,
> _Dilophosaurus_, _Deinonychus_, _Amargasaurus_, _Dicraeosaurus_ and
> _Camarasaurus_.

"Both" of those, yeah, and in the text he relies on more of that sort.

> He also evidentally regards _Ctenosauriscus_ as bipedal.

And why? Because the neural spines from a fan above the... middle of the
ribcage, where, assuming dinosaurian proportions and a completely
neornithine posture, the knee _could_ have been. :-( :-( :-(

> Ebel fails to address features discussed by Holtz and others as adaptions
> for terrestrial locomotion (i.e. arctometatarsus).

How can he address stuff he doesn't know.

> In table 1, there are several errors.  There are some sauropods with armor
> (i.e. _Saltasaurus_).  What does armor have to do with a terrestrial
> lifestyle?

In crocodiles, the armor has assumed some functions of an exoskeleton.
Notably, there are ligaments between the osteoderms that... prevent...
the... vertebral column from hanging through. =8-) The same has been
proposed for saltasaurids, which are the only sauropods that lack
hyposphenes & hypantra.

> He doesn't note that dromaeosaurids had ossified tendons.

Well, were those elongations of the caudal pre- and postzygapophyses and
chevrons (which Ebel, IIRC, doesn't know either) really ossified tendons?

>  And doesn't note the differences in many theropod taxa from the
> basalmost dinosaurs as far as pelvic morphology is concerned.

Seems not to know it.

> He also evidentally never got around to reading Bakker 1986 as he does not
> cite it . . . (sarcasm yes, I realize that no one cites every single paper
> they read)

There are such loads of interesting papers that he doesn't cite that it's
IMHO a statistically safe bet he hasn't read The Dinosaur Heresies. And what
he does cite... German translations of decades-old popular dinosaur books...
the horror, the horror. Oh, BTW, there is a French but no German translation
of The Dinosaur Heresies.

Maybe I should mention that Ebel thinks bat flight, too, evolved
underwater... because of the whale-like sonar of bats. He simply didn't know
the birds that use simple clicks to orient themselves in caves, so this
seemed like a logical conclusion.

Sigh.

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

In case you wonder what I now think about FUCHSIA... I still consider it
viable (though, unlike Ebel, I think, thanks though HP Hopp & Orsen, that
the dino was fully feathered and winged before it started swimming for a
living); although WAIR may make it superfluous. Ebel's single argument
against ground-up (as opposed to _for_ something), namely that ground birds
today keep flying rarely or never and don't tend towards more flight, is
invalid (thanks to HP Tim Williams). So while FUCHSIA appears feasible to
me, it is currently not the only alternative I can imagine. In addition, if
_Archie_ lived like a dipper (*Cinclus*), that need not tell us anything
about the origin of _bird flight_...

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

HP Chris Glen, you are learning German just to read a few papers? Admirable.
However, what was considered good scientific style in the 1930s is so
horrible that understanding it is many years away from you. Rather send the
paper, in some form, to me, and in (hopefully) a few months you'll have a
translation, along with lots of weird comments by me about how the author
slaughtered the word order, used poetic words and constructions, used
dialectal/poetic grammar, and so on. :-)

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

Copied from HP Jaime Headden, I use asterisks for Linnaean binomials in
plain text. Most other people use underscores, which I use to actually
emphasize something. Other possibilities are // (visually tilting the word
into italics...) and >< (which Dinogeorge uses for emphasis). Asterisks are
most beautiful :-)

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Eastern Europe uses a TV color system called MESECAM. -- I've noted that
people in US footage shown by Austrian TV are as yellow as the Simpsons.
Does this have something with NTSC/PAL incompatibility?

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Average length of an atoposaurid? What about 30 -- 40 cm?

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Troodontid furcula? None known with certainty. One (of *Troodon*, the one
Thulborn meant) could be a fused pair of gastralia, the other (of
*Sinornithoides*) lacks the middle part and _could_ represent a pair of
unfused clavicles (although that's not probable).

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

For something with arboreal hands and terrestrial feet, look at yourself.
For something arboreal/scansorial with arboreal hands and terrestrial feet,
I wish you good luck in your search; we can climb, but we're rather bad at
it, despite the fact that all our extremities are in general terms much,
much more mobile than any dinosaur's. -- *Microraptor zhaoianus* was,
according to the photo in Hwang et al. (AMNH Novitates), completely
incapable of sprawling, "even though" it lacked a femoral neck;
*Archaeopteryx* had pedal phalangeal proportions much like a dipper :-} ,
which means just on the terrestrial side (while *Confuciusornis* is just on
the arboreal side); and its halluces, so far never found in articulation,
were likely not completely retroverted, and perhaps even not retroverted at
all. Yes, tarsiers and galagos have long legs, and jump between trees; but
"nevertheless" they have normal grasping arboreal feet like almost all other
primates. This is the reason why they were incapable of lengthening their
metatarsals in order to lengthen their feet (BTW independently); instead
they elongated their astragali and navicularia (the latter are centralia,
tarsals that no dinosaur has). Looks awesome.