Re: the definition of Reptilia and other issues

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

> The first consideration [in devising a classification system]
> should be conceptual, rather than solving the problems of classifying
> specific individual animals whose available remains [...]
> are limited or whose differences must be observed with a microscope.'

So would you lump said worms, or what don't I understand here? ~:-|

> I response to my
> <And, contra HP Kinman, the characteristics (I'm using the more
> general word here) that most people would use to distinguish
> birds from lizards are not entirely osteological.>
> you said
> <From lizards, yes. But from "reptiles" or another group whose
> existence was
> recognised/invented/... only by scientists?>
>
> cf the comment about 'arcane' knowledge in a prior paragraph.
> When knowledge, or worse, language are available only to an elite
>  there are social problems.

This is the case with Reptilia. Do you want to abandon Reptilia? I thought
you wanted to retain it?

***************************
Araeoscelidia? Think of a Late Carboniferous/Permian lizard that isn't a
lizard :-) and has a different skull.

***************************
Heisenberg, not -burg. Pronounciation is different, and Berg means mountain
while Burg means castle.

***************************
Crown-group lizards? A crown group is a group that includes the most recent
common ancestor of all living members of a bigger group and all descendants
of said ancestor. Snakes are among the descendants of the common ancestor of
all living lizards, so they are crown-group lizards. Have a look at
http://dinosauricon.com/taxa/lepidosauromorpha.html; the crown-group lizards
including snakes are called Squamata, Lepidosauria is also a crown group,
while Lepidosauromorpha is not.

***************************
HP Ken Kinman wrote:

> P.S.  David's example of nematodes and polychaetes didn't make much sense
to
> me.  I believe that the vast majority of polychaetes have legs
(parapodia),
> but I don't think any nematodes have such appendages (am I wrong?).

I don't know, I've only heard that mentioned in a general lecture about
"zoological systematics and phylogeny of the metazoans". The professor
didn't talk about it as a very frequent phenomenon -- in most cases it is
easy to tell polychaetes and nematodes apart --, and he didn't get specific.
All I know (drawings in a book called The Diversity of Living Organisms) is
that not all nematodes look like *Caenorhabditis* (like threads = nemata);
some look sort of segmented and some have _some kind of_ appendages,
probably just spines projecting from their cuticles, but I don't know. Some
look a lot like some caterpillars.

> Unless
> he was thinking of what were once called "archiannelids", but they are
> pretty uncommon compared to other polychaetes.

Don't know.

> In any case, I doubt that
> Jefferson was talking about identifying worms from horseback.

Sure, but apparently it isn't possible "with the unarmed eye" at all to tell
these apart.