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Re: Fate of Protoarchaeopteryx
Ekaterina Amalitzkaya wrote-
> What is the current consensus on Protoarchaeopteryx. The published stuff
> pretty poorly preserved except for the feathers. Is there a strong reason
> believe it is not a badly smashed version of one of these other feathered
> forms around during that time?
The consensus hasn't changed since December, when I wrote a message to the
list regarding its position-
http://www.cmnh.org/fun/dinosaur-archive/2000Dec/msg00647.html . As far as
I know, no one's done another study, although the changes made in my data
matrix (after adjusting for Makovicky's thesis and the original
Protarchaeopteryx description on Polyglot) haven't changed its position from
"member of segnosaur-oviraptorosaur clade". Protarchaeopteryx can be
distinguished from other Liaoning non-pygostylian theropods by various
characters, some of the more obvious ones are listed below-
Sinosauropteryx has- serrationless premaxillary teeth; premaxillary teeth
not enlarged; much longer tail consisting of 64 vertebrae; coracoid not
subrectangular; shorter forelimbs; very robust manual digit I; expanded
preacetabular process; no elongate retrices.
Beipiaosaurus has- larger serrations; longer cervical vertebrae; longer,
more curved manual unguals; preacetabular process expanded; pubic peduncle
narrow; femur more robust with more prominent head; tibia much shorter;
shortened metatarsus; pedual ungual I enlarged.
Caudipteryx has- serrationless premaxillary teeth confined to anterior
section of premaxilla; no maxillary teeth; no dentary teeth; decurved
dentary tip; shorter forelimbs; third manual digit with only two phalanges;
expanded preacetabular process; very narrow third metatarsal.
Sinornithosaurus has- no basal constriction on teeth; premaxillary teeth not
enlarged; elongate caudal prezygopophyses and chevrons; more elongate
coracoid; larger sternum; longer forelimbs; more elongate manual phalanx
III-1; expanded preacetabular process; postacetabular process extends below
ischial peduncle; arctometatarsalian metatarsus; sickle claw.
cf. Sinornithosaurus (the new specimen) has- no basal constriction on teeth;
premaxillary teeth not enlarged; elongate caudal prezygopophyses and
chevrons; elongate distal caudal centra; more elongate coracoid?; longer
forelimbs; more elongate manual phalanx III-1; arctometatarsalian
metatarsus; sickle claw.
Microraptor has- premaxillary teeth not enlarged; elongate caudal
prezygopophyses and chevrons; elongate distal caudal centra; pubis convex
laterally in anterior view; arctometatarsalian metatarsus; sickle claw.
Thus, it is nearly certain Protarchaeopteryx is a distinct, valid genus.