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re: If No. 9 is a hatchling
responding to David Marjonovic's replies:
> I wonder what size the mother would have to be if No. 9 was indeed a
Well, if the meanwhile conventional wisdom is right and *Pterodactylus* &
*Germanodactylus* had a wingspan of some 2.5 m when they were adult (like
*Pterodactylus longicollum*), then I don't see any problem.
.........Well, you skipped all the candidates that are phylogenetically closer.
And, forgive me if I'm mistaken, but if you're into conventional wisdom and you
consider P. longicollum the adult, then the little pterodactylids to their
phylogenetic left, some about the same size as No. 9, are they all hatchlings
and juveniles? If so, why do they have extra-long rostra and small eyes like
adults do? Something is illogical here. I would expect a gradual trend via
ontogeny. Not a big leap in 'week two' of their young lives.
Speaking of paedomorphosis, there are dogs with shorter rostra that are adults.
They have shorter rostra than their ancestors. Monkeys have shorter rostra than
lemurs. There are people who look like children but are adults. They have
shorter rostra. You can't be sure a short rostrum is a juvenile character,
especially if the phylogenetic ancestors, in this case the scaphognathids, also
had short rostra. No. 9 just looks like its grandparents. That's all.
The key is this: evolution works one part at a time. If you're an
australopithecine first you get a human pelvis, then feet. Then you get a human
brain. Finally, way late, the chin pops on. (I'm not saying this for you,
David. You know this stuff. Web surfers may not.) In scaphognathids the skull
stayed pretty much the same in the next phylogenetic step (No. 9), but the
already diminishing tail diminished further. The proportions of the
antebrachium and metacarpus became more equalized. The feet stayed the same,
but digit V was less ossified because its so small (but it's still there).
That's about it. That's not a lot to get to No. 9. It takes more steps to get
to the long-snouted, long necked, pterodactylids with all their other skull
The trouble is, none of the literature has ever pointed to a good
rhamph/pterodac transition. It's always been a big jump to go from R. muensteri
to P. kochi or Ornithocheirus or you name it. That's old thinking. Now that
problem has been worked out. The transitions from protorosaur to pterosaur and
from 'rhamphorhynchoid' to 'pterodactyloid' are as smooth and gradual as in
synapsids to mammals. And this is one of those transitions.
Think of it: how do you get a pterodactyloid from a rhamph?
A relatively shorter weaker tail? That's a juvenile character retained in the
A relatively shorter antebrachium versus the metacarpus? That's a juvenile
character retained in the adult.
A relatively longer skull relative to the torso? That's a juvenile character
retained in the adult.
A relatively smaller naris relative to the skull? That's a juvenile character
retained in the adult.
Relatively big eyes compared to the rostrum? Well, pterodactylids aren't really
known for their big eyes. Maybe those were retained.
It starts with hormones and ends up with genes.
If the first two pterosaurs ever discovered were Scaphognathus and No. 9, then
the story would be different. You'd see the similarities. Right now you see
only the differences because of the books you've read. Stop splitting and start
David, I sent you the files you'll need to see the complete picture. I'm here
> Your challenge is to match a baby with a mother.
Nope. The fossil record is way patchy enough to spare us this challenge.
Hey, you're backing away. Listen, just find a good sister taxon. I won't be a
stickler for every skeletal detail. But I will insist that the baby, give or
take 20%, fit through the cloaca of the mother you choose. That's all you have
If you can't find a match, you're left with the next most parsimonious answer:
They're different enough to merit separate taxa.
Don't back down and end up agreeing with me. Find me a real baby!
Hope to hear from you, or anyone else who wants to accept the challenge.