Re: Conodont elements

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> Date:          Thu, 01 Jun 1995 09:11:29 +0000 (GMT)
> From:          Paul Smith <SMITHMP@ers.bham.ac.uk>
> Subject:       Re: Conodont elements
> To:            paleonet@nhm.ac.uk
> Reply-to:      paleonet@nhm.ac.uk
> Organization:  Earth Sciences, Univ of B'ham
> Priority:      normal

> > Date:          Wed, 31 May 95 17:10:15 -0600
> > From:          Andrew MacRae <macrae@pandora.geo.ucalgary.ca>
> > To:            paleonet@nhm.ac.uk
> > Subject:       Re: Conodont elements
> > Reply-to:      paleonet@nhm.ac.uk
> 
> >Andrew MacRae <macrae@pandora.geo.ucalgary.ca> wrote:
> >
> >However, I disagree that  the presence of covering tissues has "no 
> >bearing on their function".  One of the features that really puzzled 
> >me when I looked more closely at the reconstructions of Aldredge et 
> >al., 1987 for the ozarkodinid apparatus is how close together the 
> >individual S and P elements are positioned in bedding plane 
> >assemblages. 
> >One hypothesis I (and I am sure others) have considered is the  
> >possibility the bedding plane assemblages represent the "rest" or 
> >some other position of the apparatus rather than the "functional" 
> >position --  i.e. the geometry that has been reconstructed is *not* the 
> >operational geometry. 
> 
> As one of the authors of the Aldridge et al. 1987 paper, I can confirm 
> that this idea has been previously considered - in that paper (p.73) we 
> clearly stated that the reconstruction presented, and the attitude of 
> most bedding plane assemblages, is the resting position.  We were 
> not the first, the idea had previously been forwarded by, at least, 
> Lennart Jeppsson and Stefan Bengtson.
> 
> Paul Smith
> m.p.smith@bham.ac.uk
> 
I am a late entry into this debate about close association of P and S 
elements so have missed some of the info. however----I have looked 
at a large number of Oepikodus bedding plane assemblages basically of 
two styles(1) loose partially disarticulated assemblages,mostly complete,and 
almost always with the M elements paired and similarly the  Pa, and 
Pb elements paired up. (2)tightly bundled assemblages S elements in 
the middle,with theM,P, grouped as Pa,Pb,M,(left) and Pa,Pb,M,(right) 
on either side of the S element array.
Food for thought.   Ian Stewart Ecology &Evolutionary Biol. Monash 
Univ.  ian.stewart@sci.monash.edu.au