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AMNIOTE SCALES



The small, bare-skinned one (aka LN Jeff) writes:

>      SCALES are AMNIOTE traits?  I thought Tim Holtz just said synapsid 
> were probably unscaled.  What is the formal diagnosis for "Reptilia"?  
> Who diagnosed it originally and when (meaning, why is "amniota" usd 
> by cladists for the common ancestor of turtles, lepidosaurs, 
> archosaurs, AND synapsids instead of "reptilia"?)  

I recently had to chase up a couple of things relating to the life appearance
of various Carboniferous amphibians, and I've now seen 'scaly' skin in an
_Eryops_. It was described in _American Journal of Science_ back in the 1920s
I think. Furthermore, in a paper in _Biological Review_ a couple of decades
back, Bob Carroll figured ventral scales from various late Palaeozoic
amphibians, as well as from the basal synapsid _Ophiacodon_. 

(Sorry I haven't posted full refs: will do if anyone badgers me.)

I don't mean to say that Tom is *wrong*, but, hell, I'm confused. Or am I just
out of date? Jeff, don't call him Tim: just makes him mad.

BINOCULAR VISION

We're all taught that binocular vision is an adaptation allowing predators,
climbers etc to judge depth perception. But a number of non-predatory non-
climbers appear to possess it. 

(1) Maryanska has said that it was present in pachycephalosaurs - I would be
interesting if anyone could verify this as a possibility. I understand the case
is pretty hopeless, as amongst living animals, ostriches - which have
overlapping visual fields - don't actually 'see' with binocular vision. 

(2) It would also seem that living crocodiles have binocular vision. Can anyone
verify _that_? 

Then, of course, there are predators that seem to have gotten by without the
adaptation (including a number of theropods). Applying rules to the natural
world seem to be a bad idea.

I know the name for *another* new Santana theropod.

"Diplomatic immunity" "It's just been revoked" (Harris emend. 1996)
"You're using those in *public*?? Good grief!!"

DARREN NAISH
dwn194@soton.ac.uk