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Re: sauropod behaviour speculations



Stephan Pickering (stefanpickering2002@yahoo.com) wrote:

<Both investigations should be studied with care and open-mindedness, as I
believe (contra the opinions of some) that ungulates might provide one
with interesting ecological templates which might, just might, give one an
inferred glimpse, a possible interpolative framework, of how small
sauropod taxa may have been behaving near lakes and rivers.>

  You shouldn't misinterpret anything _I_ might say; I simply ask that
speculations of the behavior of extinct animals follow in trajectories
that can be tested for them, not simply inferred from a set of fluffy,
extant birds, and especially more difficult in the form of furry extant
cynodonts. Without testing, this is nothing idle banter on why
*Cetiosaurus* shouldn't be depicted as an infanticidal, matriarchal beast
when we lack evidence of babies, parental care, or even gender in pretty
much any [extinct] dinosaur, save the probably allocation of some
long-tailed specimens to males in *Confuciusornis* and probably
*Protopteryx* as well (among birds only, however; no non-avian dinosaur is
known to gender, just sexual dimorphism). However, this is off the topic I
am responding to. To understand exactly how far one can take the
ungulate/dinosaur analogue, Matt Carrano has worked on several papers that
draw attention to this data, both critically and optimistically (if you
prefer). He comes down on the side of being able to use extant data to
look at extinct, non-related species, but its clear from these papers
exactly what you can do with that data, rather than what you want to do
with what you're looking at. It may seem a pretty, involved structure to
give dinosaurs all these behaviors, inferred from elephants and pigs and
the like, for sauropods surely could have had irridescent integument a là
hummingbirds and Bakker, but its one of those things that can only be
solved with a time machine.

  Carrano, M.T. 1998. Locomotion in non-avian dinosaurs: integrating data
  from hindlimb kinematics, in vivo strains, and bone morphology.
  _Paleobiology_ 24 (4): 450-469.

  Carrano, M.T. 1999. What, if anything, is a cursor? Categories vs.
  continuua for determining locomotor habit in mammals and
  dinosaurs._Journal of Zoology, London_ 247: 29-42.

  Carrano, M.T.; Janis, C.M.; and Sepkoski, J.J., Jr. 1999. Hadrosaurs as
  ungulate parallels: Lost lifestyles and deficient data. _Acta
  Palaeontologica Polonica_ 44 (3): 237-261.

  Carrano, M.T. 2000. Homoplasy and the evolution of dinosaur locomotion.
  _Palaeobiology_ 26: 489-512.

  Carrano, M.T. 2001. Implications of limb bone scaling, curvature and
  eccentricity in mammals and non-avian dinosaurs. _Journal of Zoology,
  London_ 254: 41-55. 

  His own thesis goes into more broad explanations that much of his recent
work is the publication of:

  Carrano, M.T. (1998) The evolution of dinosaur locomotion: Functional
  morphology, biomechanics, and modern analogs. Ph.D. dissertation,
  University of Chicago, 1-424 [in 2 vols.].

  So asdie from all this:

  What small sauropods in which habitats? The only dwarf sauropods known
were found in an island system in Europe, whereas baby sauropods were
likely constrained by the locomotion and reach of their much older (and
larger) relatives. Tracks show mud-walking, and such, as well as shallow
coastal hand-prints that suggest a swimming style, but these are
mechanical in nature and do not tell us about the behavior of these
animals.

  Cheers,

=====
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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