Re: Ptero embryo

[David Peters <davidrpeters@earthlink.net>]

In a message dated 6/9/2004 6:48:39 AM Eastern Daylight Time,
bh480@scn.org
writes:

> Pterosaur embryo found in egg
>
> Just in case this has not been mentioned here yet, the new
> issue of Nature reports the discovery of a perfect
> pterosaur embryo.
> http://www.nature.com/nsu/040607/040607-6.html

Question to Dave Peters:  Does this new find corroborate what you were
seeing
in your scans?  The authors say that "_Haopterus_ most resembles this
embryo."

Mary

>>>>>.

Well, from the look of the photo it seems a bit "scrambled" compared to
the wonderful illustration above it. So far I can only understand parts
of it. I will be heading toward Washington University this morning to
see if I can access a pdf. In the meantime, if anyone can send me a pdf
[or better yet, I hi-rez jpeg], I'd appreciate it, just in case I run
into some red tape.

Like a good scientist, I'm going to test the observations before
throwing in the towel and offering congratulations.

Here is a list of inconsistencies I've found between the new embryo and
the 40 or so old "illusion" embryos I've become familiar with. And
remember, inconsistencies are not bad, they're just different.

1. the embryo is ossified
2. the embryo is not with its mother
3. the tibia is much longer than then femur
4. the sclerotic ring appears to be relatively large in relation to the
skull length
5. if the embryo is a baby Haopterus, the rostrum is much shorter and
rounder than the neonate Haopterus I found [see pterosaurinfo.com]
6. the teeth are much smaller than I see in other embryos

In addition, the record of Wang and Zhou is not good with regard to
identifying pterosaurs and parts of pterosaurs.

I have a working hypothesis that indicates the Chinese embryo may not be
an embryo at all, but rather a better explanation may be discovered in
the details. I've given a few clues to the working hypothesis above.
I'll let you all know what's cooking when my testing is complete.

Knowing that David Unwin was aware of this fossil embryo/egg helps me
understand why my abstract was rejected a few days ago by SVP, although
the evidence is not conclusive. For the record, here it is:

VIVIPARITY AND MATERNAL CARE IN PTEROSAURS AND OTHER HIGHER
PROLACERTIFORMS

Recent research has found juveniles and embryos with 30+ adult
pterosaurs. Previously overlooked and difficult to see, the impressions
of these unossified offspring were found by adjusting contrast on a
digital scan, then tracing edges.

Similar offspring were found in pterosaur sister taxa. In
<i>Cosesaurus</i> a ruptured sac is visible within the mother?s torso, a
neonate is at the birth canal and a half-size juvenile shares the slab
(along with a medusa). Like the parent, young <i>Longisquama</i> had
distal winglets and a cranial+dorsal frill. Unlike the parent, it had
short legs and a short torso, morphologically more similar to basal
pterosaurs. This ontogenetic change suggests that paedomorphosis was one
factor in the <i>Longisquama</i> to pterosaur transition.

A few putative juveniles, some with <2 cm skulls, have offspring.
Relatively short snouts and large orbits place these tiny adults close
to <i>Scaphognathus</i> and <i>Dorygnathus</i> in cladistic analysis.

Pterosaur offspring do not have proportionately larger eyes. They have a
tibia shorter than the femur, relatively large feet and a shorter
antebrachium. The rostrum may be shorter. At birth the wing finger may
be relatively longer than that of the parent and folded at every joint.
Long-necked adults have long-necked neonates. The data shows that no
more than two juveniles and two embryos are present, except in breeding
grounds where the matrix may be littered with abandoned babies. As in
bats, offspring clung to the mother, apparently beneath her and oriented
posteriorly. Maternal feeding was necessary until independence, some
time after half the adult size was reached. Rapid maturity equal to the
gestation period is presumed.

Specimens showing incomplete ossification (e.g. BMNH 37012) appear to be
on the verge of independence. Delayed ossification facilitated the
development of extremely thin-walled hollow bones. Previous associations
of pelvic shape and crest size with gender no longer appear valid
because many mothers and infants ? from <i>Longisquama</i> to the
super-crested nyctosaurs, KJ1 and KJ2 ? had large crests.

More later,

David Peters
St. Louis