Re: featherlike dermal structures

[Dinogeorge@aol.com]

In a message dated 97-06-17 14:30:20 EDT, longrich@phoenix.Princeton.EDU
(Nick Longrich) writes:

<< "Featherlike dermal structures" seems to be playing pretty fast
 and loose with the phylogeny. The tall spines on the back of an Iguana or
 Sphenodon might just as easily be called "featherlike dermal structures"
 as whatever was on Longisquama's back.>>

Don't take my word for it, see this paper:

Haubold, H. & Buffetaut, E., 1987. "Une novelle interprétation de Longisquama
insignis, reptile énigmatique du Trias supérieur d'Asie centrale [A new
interpretation of Longisquama insignis, an enigmatic reptile from the Upper
Triassic of Central Asia]," Comptes Rendus Académie des Sciences du Paris
305, Série II: 65–70.

Plus, you're more correct than you think about tall spines being "featherlike
dermal structures." In MM #2 third edition, I will develop the idea that
stegosaur plates and sauropod dorsal frills are derived forms of very
primitive pre-feathers.

<< And what is the problem with an
 ancestral furcula that was lost in herbivorous dinosaurs to loosen the
 shoulder girdle for moving quadrupedally?>>

And what is the problem with having unfused clavicles to begin with that
weren't fused into a furcula and later became unfused? And with dinosaurs
being quadrupedal (actually, scansorial), not bipedal, to begin with, so they
initially had no use for fused clavicles? Furculae are unknown in any
pre-dinosaurian archosaurs, which were all quadrupedal, as far as we know.

<< As for the furcula being "just
 like Oviraptor's" I've looked at a few maniraptoran furculae and I'll tell
 you that those things are pretty darn variable. You could probably base
 papers if not a career just on furculae in birds and even in theropods
 they vary a lot. The robust furcula with large hypocleidium seen in O.
 philoceratops is pretty unusual.  >>

Agreed. The _Longisquama_ furcula has no visible hypocleidium, as far as I
know. But neither do the furculae of _Allosaurus_ and the new allosaurid
genus from Dinosaur National Monument. The hypocleidium of _Oviraptor_ is a
derived feature.