more ?Parapsicephalus post-crania

[David Peters <davidrpeters@earthlink.net>]

Chris Bennett is correct in noting that Wellnhofer's No. 9 (1970) is
listed with the pterodactyloids of Solnhofen as a Pterodactylus juvenile
and that Parasicephalus has always been considered a rhamphorhyncoid
grade pterosaur, primarily due to the skull character of non-confluent
naris and antorbital fenestra.

The interesting thing is, when you are elbow deep in a pterosaur
cladogram you find certain trouble spots where the relationships are
difficult to ascertain. The transition from the rhamph-grade to the
pterodactyloid-grade is, for my money, the most difficult of all.
Parapsicephalus and its sister taxa, the scaphognathids, and
dorygnathids, are right in the middle of it and so understanding them is
important (to about three people on the planet).

At this point the "Pterodactyloidea" appears to be diphyletic with the
narrow-snouted scaphognaths leading toward the even narrower-snouted
germanodactylids and subsequently to the sword-snouted clades
(Dsungaripteridae + Nyctosauridae + Pteranodon + Tapejaridae). On the
other side of the family tree the toothy, broad-snouted dorygnaths
appear to lead toward the remainder of the "Pterodactyloidea". I
outlined the division between the sword snouts and straight snouts at an
SVP convention in 1997, but I didn't think, at that time, that the
division preceded the emergence of the Pterodactyloidea.

Parapsicephalus, as far as I know, is known from two three-dimensional
skulls. One was discovered over a hundred years ago and one is more
recent. They appear to be congeneric, but not conspecific. I don't know
if anyone is working with this pivotal taxon. Unwin, Lü and Bakhurina
(2000) don't even list it in there classification table.

Nick Gardner said it in one way. Let me ask a similar question: What if
Parapsicephalus is a basal pterodactyloid--one that retains the
character of a separated external naris?

The juvenile, No. 9 has a similar skull, and, perhaps because it is a
juvenile, one can make out the entire unfused nasal which arches over
the antorbital fenestra and forks distally. Beneath this fork  and above
the distal jugal is where one usually finds the external naris. Hard to
see in this case. It's tiny if it is there. Otherwise the pattern of
skull bones appears to be similar. Some crushing and ventral dislocation
of the jugal is apparent, but that can be repaired on paper. The pmx
teeth are short , curved and emerge anteriorly, unlike some species of
Dorygnathus, but like others (the variety in this taxon needs more
study). There is the illusion that one of the anterior dentary teeth is
long enough to have pierced the roof of the rostrum, just anterior to
the external naris. The cervicals are not particularly long nor gracile,
but the metacarpus is longer than in any other traditional
rhamphorhynchoid. A tiny set of terminal caudal vertebrae lies a
distance equal to a hind limb from the apparently broken off proximal
caudals. One wonders if the intervening set is in the counterplate or
otherwise lost. So, like Pterodaustro and a number of other
"pterodactyloids" the baby appears to have a tail that would just touch
the ground while standing. The posterior ilial process has an anterior
hook, something I've only seen otherwise on tapejarids and azhdarchids.
Cladistically the parapsicephalians are close to the azhdarchids and the
tapejards are on the other tree branch (I'm all alone on this one, but
that's my story and I'm stickin' to it). The phalangeal patterns in the
manus and pes are more like Dorygnathus than any other specimen (contra
Wellnhofer's interpretation.) And to top it off, a small folded pair of
phalanges under MtV can be discerned.

Wellnhofer's 1970 drawing of the specimen indicates a very clean clear
set of pedes with every phalanx dilineated in the Pterodactylus pattern.
When I looked at a scanned photograph of the specimen I get a very
different picture with the feet crossing and the digits of one foot
intermeshing with the other, making it appear, overall ,that one foot is
only as long as the metatarsal set of the other. It's a difficult call,
but I don't think Wellnhofer was correct in his interpretation.

So, with these observations in mind, I'd like to find out more about
this interesting juvenile and the other two skulls. I'd like to separate
fact from illusion and if anyone can help, I'd be glad to offer as much
assistance in return.

More later,
David Peters
St. Louis