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Re: Fwd: Are dinosaurs really reptiles? (2)
Nick was kind enough to forward this reply to my earlier query on the ancestry
of Petrolacosaurus. The 'other David' provided this list from a published work
by Müller and Reisz, reffed at the end. it must be the latest word.
This list, if it is a good one, should follow a gradual evolutionary path with
regard to morphology. Let's see if it does.
(and yes, I'm being purposefully 'folksy' about this).
okay. good start. Somewhere outside of Amniota. But where are
Utaherpeton? They're a little more plain and ordinary. Have they been
I'm seeing a pattern here: Small, flat-headed and short-toed gives rise
and short-toed. There's some logic to it. The intertemporal is gone. So
this must be an
amniote.Or is it? A fat, slow, plant-eater is the father of us all?
The pattern of giant, weird, plant-eaters continues. So it must be true.
No doubt this is an amniote [representing the Synapsida?].
Where are the plain little insect and meat eaters, like Helosuchus
Are we ignoring them because they're not intriguing? At least the tail
is long here.
Didn't early reptiles have long tails? Or was that a secondary
Suddenly we're aquatic! With a decidely long premaxilla! And long teeth!
And a long tail. And a long neck. And long toes! So derived! So early!
This one seems misplaced.
Oh, yeah, Modesto said it nested with pareaisaurs (not even on the list).
Okay. Finally a plain brown, ordinary insect-eater. Long of belly. Low
to the ground.
Don't know if the tail and toes are long or short here. Not preserved.
Oh, man. Now we're back to dull teeth, short tail, short toes and a
Kinda like Dia
Now we're back to long of belly, low to the ground again. With a skull
Not at all like Procolophon. Not flat-headed.
`--+--+--Thuringothyris and (Captorhinids)
This one (and its kin) are decidedly flat-headed. Plant eaters.
I'll have to pass on this one. Not yet in my data base. A pdf would be
This one is deidedly not flat-headed. With long toes. And it has very
Which leads us to...
Finally, a long tail and long toes. Paleothyris and Hylonomus do
resemble each other.
Insects and meat on the diet. Now we're talking...
Another close cousin. Say, isn't this fanged taxon getting uncomfortably
the Synapsida? But didn't we leave those guys way back yonder with
I know it doesn' have an intertemporal, but it looks a lot more like
Tuditanus. Those darn microsaurs. They don't have an intertemporal
either and they aren't
even amniotes. That pelvis only has room for on sacral vertebra. That
means this guy really
belongs way back there near Seymouria. A reptile imposter!
This guy deserves more respect than he gets. I'm wondering why he appears
because he's more like Thuringothyris with that flatish head and those
great big dull teeth,
...like, dare I say it... Casea ... way...back...yonder...
Suddenly, after all these 'anapsids' a diapsid! Two holes at once! Isn't
it interesting that he
went straight for two, rather than dawdling about with one or the other
for awhile? And
that's not all. Long toes. Long limbs. Long neck. Long tail. Sharp teeth.
The only taxon on this l
list, other than Araeoscelis [and Anthracodromeus] who remotely resembled
this one is
Mesosaurus...way... back ...yonder. [shudder]
yes. A good sister
line: Credit is given where credit is due, but this seems to be very scattered
famiy tree. I don't have any problem with big lumbering plant eaters giving
rise to gracile little insect-eaters or visa versa... but the change ought to
be gradual. Evolutionary. Not like this see-saw.
Next question: What were the five to ten sister genera leading up to
Herrerrasaurus? No suprageneric taxa please. And please include at least one
DP in StL
Müller, J. and Reisz, R. 2006. The Phylogeny of Early Eureptiles:
Comparing Parsimony and Bayesian Approaches in the Investigation of a
Basal Fossil Clade. Systematic Biology 55 (3): 503-511.