Re: Tanystropheus egg question

["Jaime A. Headden" <qilongia@yahoo.com>]

Trevor Dykes (ktdykes@arcor.de) wrote:

<Doesn't that imply an anaconda must be oviparous?  If so, I think they
ought to be informed of this at once.>

  Bracketing assumes _a priori_ that anacondas, as in other booid snakes,
should be oviparous until proven otherwise as other snakes and
lacertilians are similarly oviparous. It is based on observation among
snakes that booids are typically viviparous, but this is made by
observation of an in-group specialization. By similar token, all viperids
are assumed to be oviparous even though some, including *Crotalus*
(rattlesnakes) give live birth after "laying" an internal egg which
hatches (ovoviviparity). However, because the rest of snakes, including
basal snakes by recent morphological OR genetic studies would support,
were oviparous, _all_ snakes _should_ be assumed to be oviparous without
observation of a contradictory condition.

  *Tanystropheus,* as in other long-necked adults, would typically have a
short-necked juvenile. Short-necked juveniles in long-necked adults occur
in flamingos, geese, anhingas, etc., providing evidence that cervical
elongation (relative to diameter of the vertebra or neck overall) occurs
during ontogeny and the same should be expected for *Tanystropheus,*
unless proven otherwise. Basal tanystropheids, and a suggestion for
juvenile *Tanystropheus,* have shorter necks.

  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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